diff --git a/test/intl402/Temporal/PlainDate/prototype/add/basic-persian.js b/test/intl402/Temporal/PlainDate/prototype/add/basic-persian.js
new file mode 100644
index 0000000000..e4b19aaeb5
--- /dev/null
+++ b/test/intl402/Temporal/PlainDate/prototype/add/basic-persian.js
@@ -0,0 +1,298 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.add
+description: >
+  Check various basic calculations not involving leap years or constraining
+  (persian calendar)
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "persian";
+
+const years1 = new Temporal.Duration(1);
+const years1n = new Temporal.Duration(-1);
+const years4 = new Temporal.Duration(4);
+const years4n = new Temporal.Duration(-4);
+
+const date14000716 = Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 16, calendar });
+const date14010716 = Temporal.PlainDate.from({ year: 1401, monthCode: "M07", day: 16, calendar });
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years1),
+  1401, 7, "M07", 16, "add 1y",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years4),
+  1404, 7, "M07", 16, "add 4y",
+  "ap", 1404);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years1n),
+  1399, 7, "M07", 16, "subtract 1y",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years4n),
+  1396, 7, "M07", 16, "subtract 4y",
+  "ap", 1396);
+
+
+// Months
+
+const months5 = new Temporal.Duration(0, 5);
+const months5n = new Temporal.Duration(0, -5);
+const months8 = new Temporal.Duration(0, 8);
+const months8n = new Temporal.Duration(0, -8);
+const years1months2 = new Temporal.Duration(1, 2);
+const years1months2n = new Temporal.Duration(-1, -2);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(months5),
+  1400, 12, "M12", 16, "add 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M08", day: 16, calendar }).add(months5),
+  1401, 1, "M01", 16, "add 5mo with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M10", day: 1, calendar }).add(months5),
+  1399, 3, "M03", 1, "add 5mo with result in the next year on day 1 of month",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M06", day: 31, calendar }).add(months8),
+  1401, 2, "M02", 31, "add 8mo with result in the next year on day 31 of month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years1months2),
+  1401, 9, "M09", 16, "add 1y 2mo",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M11", day: 30, calendar }).add(years1months2),
+  1402, 1, "M01", 30, "add 1y 2mo with result in the next year",
+  "ap", 1402);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(months5n),
+  1400, 2, "M02", 16, "subtract 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M01", day: 16, calendar }).add(months5n),
+  1399, 8, "M08", 16, "subtract 5mo with result in the previous year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M02", day: 1, calendar }).add(months5n),
+  1397, 9, "M09", 1, "subtract 5mo with result in the previous year on day 1 of month",
+  "ap", 1397);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M02", day: 31, calendar }).add(months8n),
+  1399, 6, "M06", 31, "subtract 8mo with result in the previous year on day 31 of month",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years1months2n),
+  1399, 5, "M05", 16, "subtract 1y 2mo",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M02", day: 17, calendar }).add(years1months2n),
+  1398, 12, "M12", 17, "subtract 1y 2mo with result in the previous year",
+  "ap", 1398);
+
+// Weeks
+
+const weeks1 = new Temporal.Duration(0, 0, 1);
+const weeks1n = new Temporal.Duration(0, 0, -1);
+const weeks6 = new Temporal.Duration(0, 0, 6);
+const weeks6n = new Temporal.Duration(0, 0, -6);
+const years1weeks2 = new Temporal.Duration(1, 0, 2);
+const years1weeks2n = new Temporal.Duration(-1, 0, -2);
+const months2weeks3 = new Temporal.Duration(0, 2, 3);
+const months2weeks3n = new Temporal.Duration(0, -2, -3);
+
+const date13991228 = Temporal.PlainDate.from({ year: 1399, monthCode: "M12", day: 28, calendar });
+const date14000219 = Temporal.PlainDate.from({ year: 1400, monthCode: "M02", day: 19, calendar });
+const date14000527 = Temporal.PlainDate.from({ year: 1400, monthCode: "M05", day: 27, calendar });
+const date14000604 = Temporal.PlainDate.from({ year: 1400, monthCode: "M06", day: 4, calendar });
+const date14000627 = Temporal.PlainDate.from({ year: 1400, monthCode: "M06", day: 27, calendar });
+const date14000704 = Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 4, calendar });
+const date14000727 = Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 27, calendar });
+const date14001122 = Temporal.PlainDate.from({ year: 1400, monthCode: "M11", day: 22, calendar });
+const date14001127 = Temporal.PlainDate.from({ year: 1400, monthCode: "M11", day: 27, calendar });
+const date14001222 = Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 22, calendar });
+const date14010127 = Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 27, calendar });
+const date14010604 = Temporal.PlainDate.from({ year: 1401, monthCode: "M06", day: 4, calendar });
+
+TemporalHelpers.assertPlainDate(
+  date14000219.add(weeks1),
+  1400, 2, "M02", 26, "add 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14001222.add(weeks1),
+  1400, 12, "M12", 29, "add 1w with result on the last day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 23, calendar }).add(weeks1),
+  1401, 1, "M01", 1, "add 1w with result on the first day of the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date14000627.add(weeks1),
+  1400, 7, "M07", 3, "add 1w in a 31-day month with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14000727.add(weeks1),
+  1400, 8, "M08", 4, "add 1w in a 30-day month with result in the next month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14010127.add(weeks6),
+  1401, 3, "M03", 7, "add 6w with result in the same year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14001222.add(weeks6),
+  1401, 2, "M02", 4, "add 6w with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14001127.add(weeks6),
+  1401, 1, "M01", 10, "add 6w crossing months of 30 and 31 days",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14000627.add(weeks6),
+  1400, 8, "M08", 8, "add 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date13991228.add(years1weeks2),
+  1401, 1, "M01", 13, "add 1y 2w with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M10", day: 28, calendar }).add(months2weeks3),
+  1399, 1, "M01", 20, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M10", day: 31, calendar }).add(months2weeks3),
+  1399, 1, "M01", 21, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDate(
+  date14000219.add(weeks1n),
+  1400, 2, "M02", 12, "subtract 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M01", day: 8, calendar }).add(weeks1n),
+  1400, 1, "M01", 1, "subtract 1w with result on the first day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 7, calendar }).add(weeks1n),
+  1400, 12, "M12", 29, "subtract 1w with result on the last day of the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14000704.add(weeks1n),
+  1400, 6, "M06", 28, "subtract 1w with result in the previous 31-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 3, calendar }).add(weeks1n),
+  1400, 11, "M11", 26, "subtract 1w with result in the previous 30-day month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14000604.add(weeks6n),
+  1400, 4, "M04", 24, "subtract 6w with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14010127.add(weeks6n),
+  1400, 12, "M12", 14, "subtract 6w with result in the previous year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 8, calendar }).add(weeks6n),
+  1400, 5, "M05", 28, "subtract 6w crossing months of 30 and 31 days",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M03", day: 8, calendar }).add(weeks6n),
+  1400, 1, "M01", 28, "subtract 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1402, monthCode: "M01", day: 5, calendar }).add(years1weeks2n),
+  1400, 12, "M12", 20, "subtract 1y 2w with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M03", day: 2, calendar }).add(months2weeks3n),
+  1397, 12, "M12", 10, "subtract 2mo 3w with result in the previous year",
+  "ap", 1397);
+
+// Days
+
+const days10 = new Temporal.Duration(0, 0, 0, 10);
+const days10n = new Temporal.Duration(0, 0, 0, -10);
+const weeks2days3 = new Temporal.Duration(0, 0, 2, 3);
+const weeks2days3n = new Temporal.Duration(0, 0, -2, -3);
+const years1months2days4 = new Temporal.Duration(1, 2, 0, 4);
+const years1months2days4n = new Temporal.Duration(-1, -2, 0, -4);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(days10),
+  1400, 7, "M07", 26, "add 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 26, calendar }).add(days10),
+  1400, 8, "M08", 6, "add 10 days with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 26, calendar }).add(days10),
+  1401, 1, "M01", 7, "add 10 days with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date13991228.add(weeks2days3),
+  1400, 1, "M01", 15, "add 2w 3d with result in the next year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(years1months2days4),
+  1401, 9, "M09", 20, "add 1y 2mo 4d",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1399, monthCode: "M10", day: 20, calendar }).add(years1months2days4),
+  1400, 12, "M12", 24, "add 1y 2mo 4d with result in a month following a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M05", day: 26, calendar }).add(years1months2days4),
+  1401, 7, "M07", 30, "add 1y 2mo 4d with result in a month following a 31-day month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.add(days10n),
+  1400, 7, "M07", 6, "subtract 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 6, calendar }).add(days10n),
+  1400, 6, "M06", 27, "subtract 10 days with result in the previous month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 4, calendar }).add(days10n),
+  1400, 12, "M12", 23, "subtract 10 days with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 15, calendar }).add(weeks2days3n),
+  1400, 12, "M12", 27, "subtract 2w 3d with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14010716.add(years1months2days4n),
+  1400, 5, "M05", 12, "subtract 1y 2mo 4d",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M12", day: 4, calendar }).add(years1months2days4n),
+  1400, 9, "M09", 30, "subtract 1y 2mo 4d with result in a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14010604.add(years1months2days4n),
+  1400, 3, "M03", 31, "subtract 1y 2mo 4d with result in a 31-day month",
+  "ap", 1400);
diff --git a/test/intl402/Temporal/PlainDate/prototype/subtract/basic-persian.js b/test/intl402/Temporal/PlainDate/prototype/subtract/basic-persian.js
new file mode 100644
index 0000000000..c81a6fb35a
--- /dev/null
+++ b/test/intl402/Temporal/PlainDate/prototype/subtract/basic-persian.js
@@ -0,0 +1,298 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.subtract
+description: >
+  Check various basic calculations not involving leap years or constraining
+  (persian calendar)
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "persian";
+
+const years1 = new Temporal.Duration(-1);
+const years1n = new Temporal.Duration(1);
+const years4 = new Temporal.Duration(-4);
+const years4n = new Temporal.Duration(4);
+
+const date14000716 = Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 16, calendar });
+const date14010716 = Temporal.PlainDate.from({ year: 1401, monthCode: "M07", day: 16, calendar });
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years1),
+  1401, 7, "M07", 16, "add 1y",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years4),
+  1404, 7, "M07", 16, "add 4y",
+  "ap", 1404);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years1n),
+  1399, 7, "M07", 16, "subtract 1y",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years4n),
+  1396, 7, "M07", 16, "subtract 4y",
+  "ap", 1396);
+
+
+// Months
+
+const months5 = new Temporal.Duration(0, -5);
+const months5n = new Temporal.Duration(0, 5);
+const months8 = new Temporal.Duration(0, -8);
+const months8n = new Temporal.Duration(0, 8);
+const years1months2 = new Temporal.Duration(-1, -2);
+const years1months2n = new Temporal.Duration(1, 2);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(months5),
+  1400, 12, "M12", 16, "add 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M08", day: 16, calendar }).subtract(months5),
+  1401, 1, "M01", 16, "add 5mo with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M10", day: 1, calendar }).subtract(months5),
+  1399, 3, "M03", 1, "add 5mo with result in the next year on day 1 of month",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M06", day: 31, calendar }).subtract(months8),
+  1401, 2, "M02", 31, "add 8mo with result in the next year on day 31 of month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years1months2),
+  1401, 9, "M09", 16, "add 1y 2mo",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M11", day: 30, calendar }).subtract(years1months2),
+  1402, 1, "M01", 30, "add 1y 2mo with result in the next year",
+  "ap", 1402);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(months5n),
+  1400, 2, "M02", 16, "subtract 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M01", day: 16, calendar }).subtract(months5n),
+  1399, 8, "M08", 16, "subtract 5mo with result in the previous year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M02", day: 1, calendar }).subtract(months5n),
+  1397, 9, "M09", 1, "subtract 5mo with result in the previous year on day 1 of month",
+  "ap", 1397);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M02", day: 31, calendar }).subtract(months8n),
+  1399, 6, "M06", 31, "subtract 8mo with result in the previous year on day 31 of month",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years1months2n),
+  1399, 5, "M05", 16, "subtract 1y 2mo",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M02", day: 17, calendar }).subtract(years1months2n),
+  1398, 12, "M12", 17, "subtract 1y 2mo with result in the previous year",
+  "ap", 1398);
+
+// Weeks
+
+const weeks1 = new Temporal.Duration(0, 0, -1);
+const weeks1n = new Temporal.Duration(0, 0, 1);
+const weeks6 = new Temporal.Duration(0, 0, -6);
+const weeks6n = new Temporal.Duration(0, 0, 6);
+const years1weeks2 = new Temporal.Duration(-1, 0, -2);
+const years1weeks2n = new Temporal.Duration(1, 0, 2);
+const months2weeks3 = new Temporal.Duration(0, -2, -3);
+const months2weeks3n = new Temporal.Duration(0, 2, 3);
+
+const date13991228 = Temporal.PlainDate.from({ year: 1399, monthCode: "M12", day: 28, calendar });
+const date14000219 = Temporal.PlainDate.from({ year: 1400, monthCode: "M02", day: 19, calendar });
+const date14000527 = Temporal.PlainDate.from({ year: 1400, monthCode: "M05", day: 27, calendar });
+const date14000604 = Temporal.PlainDate.from({ year: 1400, monthCode: "M06", day: 4, calendar });
+const date14000627 = Temporal.PlainDate.from({ year: 1400, monthCode: "M06", day: 27, calendar });
+const date14000704 = Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 4, calendar });
+const date14000727 = Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 27, calendar });
+const date14001122 = Temporal.PlainDate.from({ year: 1400, monthCode: "M11", day: 22, calendar });
+const date14001127 = Temporal.PlainDate.from({ year: 1400, monthCode: "M11", day: 27, calendar });
+const date14001222 = Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 22, calendar });
+const date14010127 = Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 27, calendar });
+const date14010604 = Temporal.PlainDate.from({ year: 1401, monthCode: "M06", day: 4, calendar });
+
+TemporalHelpers.assertPlainDate(
+  date14000219.subtract(weeks1),
+  1400, 2, "M02", 26, "add 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14001222.subtract(weeks1),
+  1400, 12, "M12", 29, "add 1w with result on the last day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 23, calendar }).subtract(weeks1),
+  1401, 1, "M01", 1, "add 1w with result on the first day of the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date14000627.subtract(weeks1),
+  1400, 7, "M07", 3, "add 1w in a 31-day month with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14000727.subtract(weeks1),
+  1400, 8, "M08", 4, "add 1w in a 30-day month with result in the next month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14010127.subtract(weeks6),
+  1401, 3, "M03", 7, "add 6w with result in the same year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14001222.subtract(weeks6),
+  1401, 2, "M02", 4, "add 6w with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14001127.subtract(weeks6),
+  1401, 1, "M01", 10, "add 6w crossing months of 30 and 31 days",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  date14000627.subtract(weeks6),
+  1400, 8, "M08", 8, "add 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date13991228.subtract(years1weeks2),
+  1401, 1, "M01", 13, "add 1y 2w with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M10", day: 28, calendar }).subtract(months2weeks3),
+  1399, 1, "M01", 20, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M10", day: 31, calendar }).subtract(months2weeks3),
+  1399, 1, "M01", 21, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDate(
+  date14000219.subtract(weeks1n),
+  1400, 2, "M02", 12, "subtract 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M01", day: 8, calendar }).subtract(weeks1n),
+  1400, 1, "M01", 1, "subtract 1w with result on the first day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 7, calendar }).subtract(weeks1n),
+  1400, 12, "M12", 29, "subtract 1w with result on the last day of the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14000704.subtract(weeks1n),
+  1400, 6, "M06", 28, "subtract 1w with result in the previous 31-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 3, calendar }).subtract(weeks1n),
+  1400, 11, "M11", 26, "subtract 1w with result in the previous 30-day month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14000604.subtract(weeks6n),
+  1400, 4, "M04", 24, "subtract 6w with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14010127.subtract(weeks6n),
+  1400, 12, "M12", 14, "subtract 6w with result in the previous year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 8, calendar }).subtract(weeks6n),
+  1400, 5, "M05", 28, "subtract 6w crossing months of 30 and 31 days",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M03", day: 8, calendar }).subtract(weeks6n),
+  1400, 1, "M01", 28, "subtract 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1402, monthCode: "M01", day: 5, calendar }).subtract(years1weeks2n),
+  1400, 12, "M12", 20, "subtract 1y 2w with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1398, monthCode: "M03", day: 2, calendar }).subtract(months2weeks3n),
+  1397, 12, "M12", 10, "subtract 2mo 3w with result in the previous year",
+  "ap", 1397);
+
+// Days
+
+const days10 = new Temporal.Duration(0, 0, 0, -10);
+const days10n = new Temporal.Duration(0, 0, 0, 10);
+const weeks2days3 = new Temporal.Duration(0, 0, -2, -3);
+const weeks2days3n = new Temporal.Duration(0, 0, 2, 3);
+const years1months2days4 = new Temporal.Duration(-1, -2, 0, -4);
+const years1months2days4n = new Temporal.Duration(1, 2, 0, 4);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(days10),
+  1400, 7, "M07", 26, "add 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 26, calendar }).subtract(days10),
+  1400, 8, "M08", 6, "add 10 days with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M12", day: 26, calendar }).subtract(days10),
+  1401, 1, "M01", 7, "add 10 days with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date13991228.subtract(weeks2days3),
+  1400, 1, "M01", 15, "add 2w 3d with result in the next year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(years1months2days4),
+  1401, 9, "M09", 20, "add 1y 2mo 4d",
+  "ap", 1401);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1399, monthCode: "M10", day: 20, calendar }).subtract(years1months2days4),
+  1400, 12, "M12", 24, "add 1y 2mo 4d with result in a month following a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M05", day: 26, calendar }).subtract(years1months2days4),
+  1401, 7, "M07", 30, "add 1y 2mo 4d with result in a month following a 31-day month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDate(
+  date14000716.subtract(days10n),
+  1400, 7, "M07", 6, "subtract 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1400, monthCode: "M07", day: 6, calendar }).subtract(days10n),
+  1400, 6, "M06", 27, "subtract 10 days with result in the previous month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 4, calendar }).subtract(days10n),
+  1400, 12, "M12", 23, "subtract 10 days with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M01", day: 15, calendar }).subtract(weeks2days3n),
+  1400, 12, "M12", 27, "subtract 2w 3d with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDate(
+  date14010716.subtract(years1months2days4n),
+  1400, 5, "M05", 12, "subtract 1y 2mo 4d",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 1401, monthCode: "M12", day: 4, calendar }).subtract(years1months2days4n),
+  1400, 9, "M09", 30, "subtract 1y 2mo 4d with result in a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDate(
+  date14010604.subtract(years1months2days4n),
+  1400, 3, "M03", 31, "subtract 1y 2mo 4d with result in a 31-day month",
+  "ap", 1400);
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/add/basic-persian.js b/test/intl402/Temporal/PlainDateTime/prototype/add/basic-persian.js
new file mode 100644
index 0000000000..168c62924c
--- /dev/null
+++ b/test/intl402/Temporal/PlainDateTime/prototype/add/basic-persian.js
@@ -0,0 +1,298 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.add
+description: >
+  Check various basic calculations not involving leap years or constraining
+  (persian calendar)
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "persian";
+
+const years1 = new Temporal.Duration(1);
+const years1n = new Temporal.Duration(-1);
+const years4 = new Temporal.Duration(4);
+const years4n = new Temporal.Duration(-4);
+
+const date14000716 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 16, hour: 12, minute: 34, calendar });
+const date14010716 = Temporal.PlainDateTime.from({ year: 1401, monthCode: "M07", day: 16, hour: 12, minute: 34, calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1),
+  1401, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 1y",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years4),
+  1404, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 4y",
+  "ap", 1404);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1n),
+  1399, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 1y",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years4n),
+  1396, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 4y",
+  "ap", 1396);
+
+
+// Months
+
+const months5 = new Temporal.Duration(0, 5);
+const months5n = new Temporal.Duration(0, -5);
+const months8 = new Temporal.Duration(0, 8);
+const months8n = new Temporal.Duration(0, -8);
+const years1months2 = new Temporal.Duration(1, 2);
+const years1months2n = new Temporal.Duration(-1, -2);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(months5),
+  1400, 12, "M12", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M08", day: 16, hour: 12, minute: 34, calendar }).add(months5),
+  1401, 1, "M01", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M10", day: 1, hour: 12, minute: 34, calendar }).add(months5),
+  1399, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year on day 1 of month",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M06", day: 31, hour: 12, minute: 34, calendar }).add(months8),
+  1401, 2, "M02", 31, 12, 34, 0, 0, 0, 0, "add 8mo with result in the next year on day 31 of month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1months2),
+  1401, 9, "M09", 16, 12, 34, 0, 0, 0, 0, "add 1y 2mo",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M11", day: 30, hour: 12, minute: 34, calendar }).add(years1months2),
+  1402, 1, "M01", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo with result in the next year",
+  "ap", 1402);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(months5n),
+  1400, 2, "M02", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M01", day: 16, hour: 12, minute: 34, calendar }).add(months5n),
+  1399, 8, "M08", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M02", day: 1, hour: 12, minute: 34, calendar }).add(months5n),
+  1397, 9, "M09", 1, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year on day 1 of month",
+  "ap", 1397);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M02", day: 31, hour: 12, minute: 34, calendar }).add(months8n),
+  1399, 6, "M06", 31, 12, 34, 0, 0, 0, 0, "subtract 8mo with result in the previous year on day 31 of month",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1months2n),
+  1399, 5, "M05", 16, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M02", day: 17, hour: 12, minute: 34, calendar }).add(years1months2n),
+  1398, 12, "M12", 17, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo with result in the previous year",
+  "ap", 1398);
+
+// Weeks
+
+const weeks1 = new Temporal.Duration(0, 0, 1);
+const weeks1n = new Temporal.Duration(0, 0, -1);
+const weeks6 = new Temporal.Duration(0, 0, 6);
+const weeks6n = new Temporal.Duration(0, 0, -6);
+const years1weeks2 = new Temporal.Duration(1, 0, 2);
+const years1weeks2n = new Temporal.Duration(-1, 0, -2);
+const months2weeks3 = new Temporal.Duration(0, 2, 3);
+const months2weeks3n = new Temporal.Duration(0, -2, -3);
+
+const date13991228 = Temporal.PlainDateTime.from({ year: 1399, monthCode: "M12", day: 28, hour: 12, minute: 34, calendar });
+const date14000219 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M02", day: 19, hour: 12, minute: 34, calendar });
+const date14000527 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M05", day: 27, hour: 12, minute: 34, calendar });
+const date14000604 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M06", day: 4, hour: 12, minute: 34, calendar });
+const date14000627 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M06", day: 27, hour: 12, minute: 34, calendar });
+const date14000704 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 4, hour: 12, minute: 34, calendar });
+const date14000727 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 27, hour: 12, minute: 34, calendar });
+const date14001122 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M11", day: 22, hour: 12, minute: 34, calendar });
+const date14001127 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M11", day: 27, hour: 12, minute: 34, calendar });
+const date14001222 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 22, hour: 12, minute: 34, calendar });
+const date14010127 = Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 27, hour: 12, minute: 34, calendar });
+const date14010604 = Temporal.PlainDateTime.from({ year: 1401, monthCode: "M06", day: 4, hour: 12, minute: 34, calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.add(weeks1),
+  1400, 2, "M02", 26, 12, 34, 0, 0, 0, 0, "add 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.add(weeks1),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "add 1w with result on the last day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 23, hour: 12, minute: 34, calendar }).add(weeks1),
+  1401, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "add 1w with result on the first day of the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000627.add(weeks1),
+  1400, 7, "M07", 3, 12, 34, 0, 0, 0, 0, "add 1w in a 31-day month with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14000727.add(weeks1),
+  1400, 8, "M08", 4, 12, 34, 0, 0, 0, 0, "add 1w in a 30-day month with result in the next month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010127.add(weeks6),
+  1401, 3, "M03", 7, 12, 34, 0, 0, 0, 0, "add 6w with result in the same year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.add(weeks6),
+  1401, 2, "M02", 4, 12, 34, 0, 0, 0, 0, "add 6w with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001127.add(weeks6),
+  1401, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 30 and 31 days",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000627.add(weeks6),
+  1400, 8, "M08", 8, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.add(years1weeks2),
+  1401, 1, "M01", 13, 12, 34, 0, 0, 0, 0, "add 1y 2w with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M10", day: 28, hour: 12, minute: 34, calendar }).add(months2weeks3),
+  1399, 1, "M01", 20, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M10", day: 31, hour: 12, minute: 34, calendar }).add(months2weeks3),
+  1399, 1, "M01", 21, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.add(weeks1n),
+  1400, 2, "M02", 12, 12, 34, 0, 0, 0, 0, "subtract 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M01", day: 8, hour: 12, minute: 34, calendar }).add(weeks1n),
+  1400, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the first day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 7, hour: 12, minute: 34, calendar }).add(weeks1n),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the last day of the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000704.add(weeks1n),
+  1400, 6, "M06", 28, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 31-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 3, hour: 12, minute: 34, calendar }).add(weeks1n),
+  1400, 11, "M11", 26, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 30-day month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000604.add(weeks6n),
+  1400, 4, "M04", 24, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010127.add(weeks6n),
+  1400, 12, "M12", 14, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the previous year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 8, hour: 12, minute: 34, calendar }).add(weeks6n),
+  1400, 5, "M05", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 30 and 31 days",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M03", day: 8, hour: 12, minute: 34, calendar }).add(weeks6n),
+  1400, 1, "M01", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1402, monthCode: "M01", day: 5, hour: 12, minute: 34, calendar }).add(years1weeks2n),
+  1400, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 1y 2w with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M03", day: 2, hour: 12, minute: 34, calendar }).add(months2weeks3n),
+  1397, 12, "M12", 10, 12, 34, 0, 0, 0, 0, "subtract 2mo 3w with result in the previous year",
+  "ap", 1397);
+
+// Days
+
+const days10 = new Temporal.Duration(0, 0, 0, 10);
+const days10n = new Temporal.Duration(0, 0, 0, -10);
+const weeks2days3 = new Temporal.Duration(0, 0, 2, 3);
+const weeks2days3n = new Temporal.Duration(0, 0, -2, -3);
+const years1months2days4 = new Temporal.Duration(1, 2, 0, 4);
+const years1months2days4n = new Temporal.Duration(-1, -2, 0, -4);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(days10),
+  1400, 7, "M07", 26, 12, 34, 0, 0, 0, 0, "add 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 26, hour: 12, minute: 34, calendar }).add(days10),
+  1400, 8, "M08", 6, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 26, hour: 12, minute: 34, calendar }).add(days10),
+  1401, 1, "M01", 7, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.add(weeks2days3),
+  1400, 1, "M01", 15, 12, 34, 0, 0, 0, 0, "add 2w 3d with result in the next year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1months2days4),
+  1401, 9, "M09", 20, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1399, monthCode: "M10", day: 20, hour: 12, minute: 34, calendar }).add(years1months2days4),
+  1400, 12, "M12", 24, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M05", day: 26, hour: 12, minute: 34, calendar }).add(years1months2days4),
+  1401, 7, "M07", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 31-day month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(days10n),
+  1400, 7, "M07", 6, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 6, hour: 12, minute: 34, calendar }).add(days10n),
+  1400, 6, "M06", 27, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 4, hour: 12, minute: 34, calendar }).add(days10n),
+  1400, 12, "M12", 23, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 15, hour: 12, minute: 34, calendar }).add(weeks2days3n),
+  1400, 12, "M12", 27, 12, 34, 0, 0, 0, 0, "subtract 2w 3d with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010716.add(years1months2days4n),
+  1400, 5, "M05", 12, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M12", day: 4, hour: 12, minute: 34, calendar }).add(years1months2days4n),
+  1400, 9, "M09", 30, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010604.add(years1months2days4n),
+  1400, 3, "M03", 31, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 31-day month",
+  "ap", 1400);
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-persian.js b/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-persian.js
new file mode 100644
index 0000000000..5a208ba757
--- /dev/null
+++ b/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-persian.js
@@ -0,0 +1,298 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.subtract
+description: >
+  Check various basic calculations not involving leap years or constraining
+  (persian calendar)
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "persian";
+
+const years1 = new Temporal.Duration(-1);
+const years1n = new Temporal.Duration(1);
+const years4 = new Temporal.Duration(-4);
+const years4n = new Temporal.Duration(4);
+
+const date14000716 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 16, hour: 12, minute: 34, calendar });
+const date14010716 = Temporal.PlainDateTime.from({ year: 1401, monthCode: "M07", day: 16, hour: 12, minute: 34, calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1),
+  1401, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 1y",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years4),
+  1404, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 4y",
+  "ap", 1404);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1n),
+  1399, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 1y",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years4n),
+  1396, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 4y",
+  "ap", 1396);
+
+
+// Months
+
+const months5 = new Temporal.Duration(0, -5);
+const months5n = new Temporal.Duration(0, 5);
+const months8 = new Temporal.Duration(0, -8);
+const months8n = new Temporal.Duration(0, 8);
+const years1months2 = new Temporal.Duration(-1, -2);
+const years1months2n = new Temporal.Duration(1, 2);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(months5),
+  1400, 12, "M12", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M08", day: 16, hour: 12, minute: 34, calendar }).subtract(months5),
+  1401, 1, "M01", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M10", day: 1, hour: 12, minute: 34, calendar }).subtract(months5),
+  1399, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year on day 1 of month",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M06", day: 31, hour: 12, minute: 34, calendar }).subtract(months8),
+  1401, 2, "M02", 31, 12, 34, 0, 0, 0, 0, "add 8mo with result in the next year on day 31 of month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1months2),
+  1401, 9, "M09", 16, 12, 34, 0, 0, 0, 0, "add 1y 2mo",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M11", day: 30, hour: 12, minute: 34, calendar }).subtract(years1months2),
+  1402, 1, "M01", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo with result in the next year",
+  "ap", 1402);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(months5n),
+  1400, 2, "M02", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M01", day: 16, hour: 12, minute: 34, calendar }).subtract(months5n),
+  1399, 8, "M08", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M02", day: 1, hour: 12, minute: 34, calendar }).subtract(months5n),
+  1397, 9, "M09", 1, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year on day 1 of month",
+  "ap", 1397);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M02", day: 31, hour: 12, minute: 34, calendar }).subtract(months8n),
+  1399, 6, "M06", 31, 12, 34, 0, 0, 0, 0, "subtract 8mo with result in the previous year on day 31 of month",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1months2n),
+  1399, 5, "M05", 16, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M02", day: 17, hour: 12, minute: 34, calendar }).subtract(years1months2n),
+  1398, 12, "M12", 17, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo with result in the previous year",
+  "ap", 1398);
+
+// Weeks
+
+const weeks1 = new Temporal.Duration(0, 0, -1);
+const weeks1n = new Temporal.Duration(0, 0, 1);
+const weeks6 = new Temporal.Duration(0, 0, -6);
+const weeks6n = new Temporal.Duration(0, 0, 6);
+const years1weeks2 = new Temporal.Duration(-1, 0, -2);
+const years1weeks2n = new Temporal.Duration(1, 0, 2);
+const months2weeks3 = new Temporal.Duration(0, -2, -3);
+const months2weeks3n = new Temporal.Duration(0, 2, 3);
+
+const date13991228 = Temporal.PlainDateTime.from({ year: 1399, monthCode: "M12", day: 28, hour: 12, minute: 34, calendar });
+const date14000219 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M02", day: 19, hour: 12, minute: 34, calendar });
+const date14000527 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M05", day: 27, hour: 12, minute: 34, calendar });
+const date14000604 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M06", day: 4, hour: 12, minute: 34, calendar });
+const date14000627 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M06", day: 27, hour: 12, minute: 34, calendar });
+const date14000704 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 4, hour: 12, minute: 34, calendar });
+const date14000727 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 27, hour: 12, minute: 34, calendar });
+const date14001122 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M11", day: 22, hour: 12, minute: 34, calendar });
+const date14001127 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M11", day: 27, hour: 12, minute: 34, calendar });
+const date14001222 = Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 22, hour: 12, minute: 34, calendar });
+const date14010127 = Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 27, hour: 12, minute: 34, calendar });
+const date14010604 = Temporal.PlainDateTime.from({ year: 1401, monthCode: "M06", day: 4, hour: 12, minute: 34, calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.subtract(weeks1),
+  1400, 2, "M02", 26, 12, 34, 0, 0, 0, 0, "add 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.subtract(weeks1),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "add 1w with result on the last day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 23, hour: 12, minute: 34, calendar }).subtract(weeks1),
+  1401, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "add 1w with result on the first day of the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000627.subtract(weeks1),
+  1400, 7, "M07", 3, 12, 34, 0, 0, 0, 0, "add 1w in a 31-day month with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14000727.subtract(weeks1),
+  1400, 8, "M08", 4, 12, 34, 0, 0, 0, 0, "add 1w in a 30-day month with result in the next month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010127.subtract(weeks6),
+  1401, 3, "M03", 7, 12, 34, 0, 0, 0, 0, "add 6w with result in the same year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.subtract(weeks6),
+  1401, 2, "M02", 4, 12, 34, 0, 0, 0, 0, "add 6w with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001127.subtract(weeks6),
+  1401, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 30 and 31 days",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000627.subtract(weeks6),
+  1400, 8, "M08", 8, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.subtract(years1weeks2),
+  1401, 1, "M01", 13, 12, 34, 0, 0, 0, 0, "add 1y 2w with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M10", day: 28, hour: 12, minute: 34, calendar }).subtract(months2weeks3),
+  1399, 1, "M01", 20, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M10", day: 31, hour: 12, minute: 34, calendar }).subtract(months2weeks3),
+  1399, 1, "M01", 21, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.subtract(weeks1n),
+  1400, 2, "M02", 12, 12, 34, 0, 0, 0, 0, "subtract 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M01", day: 8, hour: 12, minute: 34, calendar }).subtract(weeks1n),
+  1400, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the first day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 7, hour: 12, minute: 34, calendar }).subtract(weeks1n),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the last day of the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000704.subtract(weeks1n),
+  1400, 6, "M06", 28, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 31-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 3, hour: 12, minute: 34, calendar }).subtract(weeks1n),
+  1400, 11, "M11", 26, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 30-day month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000604.subtract(weeks6n),
+  1400, 4, "M04", 24, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010127.subtract(weeks6n),
+  1400, 12, "M12", 14, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the previous year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 8, hour: 12, minute: 34, calendar }).subtract(weeks6n),
+  1400, 5, "M05", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 30 and 31 days",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M03", day: 8, hour: 12, minute: 34, calendar }).subtract(weeks6n),
+  1400, 1, "M01", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1402, monthCode: "M01", day: 5, hour: 12, minute: 34, calendar }).subtract(years1weeks2n),
+  1400, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 1y 2w with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1398, monthCode: "M03", day: 2, hour: 12, minute: 34, calendar }).subtract(months2weeks3n),
+  1397, 12, "M12", 10, 12, 34, 0, 0, 0, 0, "subtract 2mo 3w with result in the previous year",
+  "ap", 1397);
+
+// Days
+
+const days10 = new Temporal.Duration(0, 0, 0, -10);
+const days10n = new Temporal.Duration(0, 0, 0, 10);
+const weeks2days3 = new Temporal.Duration(0, 0, -2, -3);
+const weeks2days3n = new Temporal.Duration(0, 0, 2, 3);
+const years1months2days4 = new Temporal.Duration(-1, -2, 0, -4);
+const years1months2days4n = new Temporal.Duration(1, 2, 0, 4);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(days10),
+  1400, 7, "M07", 26, 12, 34, 0, 0, 0, 0, "add 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 26, hour: 12, minute: 34, calendar }).subtract(days10),
+  1400, 8, "M08", 6, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M12", day: 26, hour: 12, minute: 34, calendar }).subtract(days10),
+  1401, 1, "M01", 7, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.subtract(weeks2days3),
+  1400, 1, "M01", 15, 12, 34, 0, 0, 0, 0, "add 2w 3d with result in the next year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1months2days4),
+  1401, 9, "M09", 20, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1399, monthCode: "M10", day: 20, hour: 12, minute: 34, calendar }).subtract(years1months2days4),
+  1400, 12, "M12", 24, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M05", day: 26, hour: 12, minute: 34, calendar }).subtract(years1months2days4),
+  1401, 7, "M07", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 31-day month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(days10n),
+  1400, 7, "M07", 6, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1400, monthCode: "M07", day: 6, hour: 12, minute: 34, calendar }).subtract(days10n),
+  1400, 6, "M06", 27, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 4, hour: 12, minute: 34, calendar }).subtract(days10n),
+  1400, 12, "M12", 23, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M01", day: 15, hour: 12, minute: 34, calendar }).subtract(weeks2days3n),
+  1400, 12, "M12", 27, 12, 34, 0, 0, 0, 0, "subtract 2w 3d with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010716.subtract(years1months2days4n),
+  1400, 5, "M05", 12, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 1401, monthCode: "M12", day: 4, hour: 12, minute: 34, calendar }).subtract(years1months2days4n),
+  1400, 9, "M09", 30, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010604.subtract(years1months2days4n),
+  1400, 3, "M03", 31, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 31-day month",
+  "ap", 1400);
diff --git a/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-persian.js b/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-persian.js
new file mode 100644
index 0000000000..bfe0b2bfa9
--- /dev/null
+++ b/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-persian.js
@@ -0,0 +1,298 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.add
+description: >
+  Check various basic calculations not involving leap years or constraining
+  (persian calendar)
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "persian";
+
+const years1 = new Temporal.Duration(1);
+const years1n = new Temporal.Duration(-1);
+const years4 = new Temporal.Duration(4);
+const years4n = new Temporal.Duration(-4);
+
+const date14000716 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14010716 = Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M07", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1).toPlainDateTime(),
+  1401, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 1y",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years4).toPlainDateTime(),
+  1404, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 4y",
+  "ap", 1404);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1n).toPlainDateTime(),
+  1399, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 1y",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years4n).toPlainDateTime(),
+  1396, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 4y",
+  "ap", 1396);
+
+
+// Months
+
+const months5 = new Temporal.Duration(0, 5);
+const months5n = new Temporal.Duration(0, -5);
+const months8 = new Temporal.Duration(0, 8);
+const months8n = new Temporal.Duration(0, -8);
+const years1months2 = new Temporal.Duration(1, 2);
+const years1months2n = new Temporal.Duration(-1, -2);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(months5).toPlainDateTime(),
+  1400, 12, "M12", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M08", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months5).toPlainDateTime(),
+  1401, 1, "M01", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M10", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months5).toPlainDateTime(),
+  1399, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year on day 1 of month",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M06", day: 31, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months8).toPlainDateTime(),
+  1401, 2, "M02", 31, 12, 34, 0, 0, 0, 0, "add 8mo with result in the next year on day 31 of month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1months2).toPlainDateTime(),
+  1401, 9, "M09", 16, 12, 34, 0, 0, 0, 0, "add 1y 2mo",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M11", day: 30, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(years1months2).toPlainDateTime(),
+  1402, 1, "M01", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo with result in the next year",
+  "ap", 1402);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(months5n).toPlainDateTime(),
+  1400, 2, "M02", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M01", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months5n).toPlainDateTime(),
+  1399, 8, "M08", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M02", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months5n).toPlainDateTime(),
+  1397, 9, "M09", 1, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year on day 1 of month",
+  "ap", 1397);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M02", day: 31, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months8n).toPlainDateTime(),
+  1399, 6, "M06", 31, 12, 34, 0, 0, 0, 0, "subtract 8mo with result in the previous year on day 31 of month",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1months2n).toPlainDateTime(),
+  1399, 5, "M05", 16, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M02", day: 17, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(years1months2n).toPlainDateTime(),
+  1398, 12, "M12", 17, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo with result in the previous year",
+  "ap", 1398);
+
+// Weeks
+
+const weeks1 = new Temporal.Duration(0, 0, 1);
+const weeks1n = new Temporal.Duration(0, 0, -1);
+const weeks6 = new Temporal.Duration(0, 0, 6);
+const weeks6n = new Temporal.Duration(0, 0, -6);
+const years1weeks2 = new Temporal.Duration(1, 0, 2);
+const years1weeks2n = new Temporal.Duration(-1, 0, -2);
+const months2weeks3 = new Temporal.Duration(0, 2, 3);
+const months2weeks3n = new Temporal.Duration(0, -2, -3);
+
+const date13991228 = Temporal.ZonedDateTime.from({ year: 1399, monthCode: "M12", day: 28, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000219 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M02", day: 19, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000527 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M05", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000604 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M06", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000627 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M06", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000704 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000727 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14001122 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M11", day: 22, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14001127 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M11", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14001222 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 22, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14010127 = Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14010604 = Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M06", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.add(weeks1).toPlainDateTime(),
+  1400, 2, "M02", 26, 12, 34, 0, 0, 0, 0, "add 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.add(weeks1).toPlainDateTime(),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "add 1w with result on the last day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 23, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks1).toPlainDateTime(),
+  1401, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "add 1w with result on the first day of the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000627.add(weeks1).toPlainDateTime(),
+  1400, 7, "M07", 3, 12, 34, 0, 0, 0, 0, "add 1w in a 31-day month with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14000727.add(weeks1).toPlainDateTime(),
+  1400, 8, "M08", 4, 12, 34, 0, 0, 0, 0, "add 1w in a 30-day month with result in the next month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010127.add(weeks6).toPlainDateTime(),
+  1401, 3, "M03", 7, 12, 34, 0, 0, 0, 0, "add 6w with result in the same year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.add(weeks6).toPlainDateTime(),
+  1401, 2, "M02", 4, 12, 34, 0, 0, 0, 0, "add 6w with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001127.add(weeks6).toPlainDateTime(),
+  1401, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 30 and 31 days",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000627.add(weeks6).toPlainDateTime(),
+  1400, 8, "M08", 8, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.add(years1weeks2).toPlainDateTime(),
+  1401, 1, "M01", 13, 12, 34, 0, 0, 0, 0, "add 1y 2w with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M10", day: 28, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months2weeks3).toPlainDateTime(),
+  1399, 1, "M01", 20, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M10", day: 31, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months2weeks3).toPlainDateTime(),
+  1399, 1, "M01", 21, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.add(weeks1n).toPlainDateTime(),
+  1400, 2, "M02", 12, 12, 34, 0, 0, 0, 0, "subtract 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M01", day: 8, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks1n).toPlainDateTime(),
+  1400, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the first day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 7, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks1n).toPlainDateTime(),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the last day of the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000704.add(weeks1n).toPlainDateTime(),
+  1400, 6, "M06", 28, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 31-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 3, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks1n).toPlainDateTime(),
+  1400, 11, "M11", 26, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 30-day month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000604.add(weeks6n).toPlainDateTime(),
+  1400, 4, "M04", 24, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010127.add(weeks6n).toPlainDateTime(),
+  1400, 12, "M12", 14, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the previous year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 8, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks6n).toPlainDateTime(),
+  1400, 5, "M05", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 30 and 31 days",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M03", day: 8, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks6n).toPlainDateTime(),
+  1400, 1, "M01", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1402, monthCode: "M01", day: 5, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(years1weeks2n).toPlainDateTime(),
+  1400, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 1y 2w with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M03", day: 2, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(months2weeks3n).toPlainDateTime(),
+  1397, 12, "M12", 10, 12, 34, 0, 0, 0, 0, "subtract 2mo 3w with result in the previous year",
+  "ap", 1397);
+
+// Days
+
+const days10 = new Temporal.Duration(0, 0, 0, 10);
+const days10n = new Temporal.Duration(0, 0, 0, -10);
+const weeks2days3 = new Temporal.Duration(0, 0, 2, 3);
+const weeks2days3n = new Temporal.Duration(0, 0, -2, -3);
+const years1months2days4 = new Temporal.Duration(1, 2, 0, 4);
+const years1months2days4n = new Temporal.Duration(-1, -2, 0, -4);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(days10).toPlainDateTime(),
+  1400, 7, "M07", 26, 12, 34, 0, 0, 0, 0, "add 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 26, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(days10).toPlainDateTime(),
+  1400, 8, "M08", 6, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 26, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(days10).toPlainDateTime(),
+  1401, 1, "M01", 7, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.add(weeks2days3).toPlainDateTime(),
+  1400, 1, "M01", 15, 12, 34, 0, 0, 0, 0, "add 2w 3d with result in the next year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(years1months2days4).toPlainDateTime(),
+  1401, 9, "M09", 20, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1399, monthCode: "M10", day: 20, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(years1months2days4).toPlainDateTime(),
+  1400, 12, "M12", 24, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M05", day: 26, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(years1months2days4).toPlainDateTime(),
+  1401, 7, "M07", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 31-day month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.add(days10n).toPlainDateTime(),
+  1400, 7, "M07", 6, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 6, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(days10n).toPlainDateTime(),
+  1400, 6, "M06", 27, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(days10n).toPlainDateTime(),
+  1400, 12, "M12", 23, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(weeks2days3n).toPlainDateTime(),
+  1400, 12, "M12", 27, 12, 34, 0, 0, 0, 0, "subtract 2w 3d with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010716.add(years1months2days4n).toPlainDateTime(),
+  1400, 5, "M05", 12, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M12", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar }).add(years1months2days4n).toPlainDateTime(),
+  1400, 9, "M09", 30, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010604.add(years1months2days4n).toPlainDateTime(),
+  1400, 3, "M03", 31, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 31-day month",
+  "ap", 1400);
diff --git a/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-persian.js b/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-persian.js
new file mode 100644
index 0000000000..436e283ddf
--- /dev/null
+++ b/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-persian.js
@@ -0,0 +1,298 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.subtract
+description: >
+  Check various basic calculations not involving leap years or constraining
+  (persian calendar)
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "persian";
+
+const years1 = new Temporal.Duration(-1);
+const years1n = new Temporal.Duration(1);
+const years4 = new Temporal.Duration(-4);
+const years4n = new Temporal.Duration(4);
+
+const date14000716 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14010716 = Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M07", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1).toPlainDateTime(),
+  1401, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 1y",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years4).toPlainDateTime(),
+  1404, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "add 4y",
+  "ap", 1404);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1n).toPlainDateTime(),
+  1399, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 1y",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years4n).toPlainDateTime(),
+  1396, 7, "M07", 16, 12, 34, 0, 0, 0, 0, "subtract 4y",
+  "ap", 1396);
+
+
+// Months
+
+const months5 = new Temporal.Duration(0, -5);
+const months5n = new Temporal.Duration(0, 5);
+const months8 = new Temporal.Duration(0, -8);
+const months8n = new Temporal.Duration(0, 8);
+const years1months2 = new Temporal.Duration(-1, -2);
+const years1months2n = new Temporal.Duration(1, 2);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(months5).toPlainDateTime(),
+  1400, 12, "M12", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M08", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months5).toPlainDateTime(),
+  1401, 1, "M01", 16, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M10", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months5).toPlainDateTime(),
+  1399, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "add 5mo with result in the next year on day 1 of month",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M06", day: 31, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months8).toPlainDateTime(),
+  1401, 2, "M02", 31, 12, 34, 0, 0, 0, 0, "add 8mo with result in the next year on day 31 of month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1months2).toPlainDateTime(),
+  1401, 9, "M09", 16, 12, 34, 0, 0, 0, 0, "add 1y 2mo",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M11", day: 30, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(years1months2).toPlainDateTime(),
+  1402, 1, "M01", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo with result in the next year",
+  "ap", 1402);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(months5n).toPlainDateTime(),
+  1400, 2, "M02", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M01", day: 16, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months5n).toPlainDateTime(),
+  1399, 8, "M08", 16, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M02", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months5n).toPlainDateTime(),
+  1397, 9, "M09", 1, 12, 34, 0, 0, 0, 0, "subtract 5mo with result in the previous year on day 1 of month",
+  "ap", 1397);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M02", day: 31, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months8n).toPlainDateTime(),
+  1399, 6, "M06", 31, 12, 34, 0, 0, 0, 0, "subtract 8mo with result in the previous year on day 31 of month",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1months2n).toPlainDateTime(),
+  1399, 5, "M05", 16, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M02", day: 17, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(years1months2n).toPlainDateTime(),
+  1398, 12, "M12", 17, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo with result in the previous year",
+  "ap", 1398);
+
+// Weeks
+
+const weeks1 = new Temporal.Duration(0, 0, -1);
+const weeks1n = new Temporal.Duration(0, 0, 1);
+const weeks6 = new Temporal.Duration(0, 0, -6);
+const weeks6n = new Temporal.Duration(0, 0, 6);
+const years1weeks2 = new Temporal.Duration(-1, 0, -2);
+const years1weeks2n = new Temporal.Duration(1, 0, 2);
+const months2weeks3 = new Temporal.Duration(0, -2, -3);
+const months2weeks3n = new Temporal.Duration(0, 2, 3);
+
+const date13991228 = Temporal.ZonedDateTime.from({ year: 1399, monthCode: "M12", day: 28, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000219 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M02", day: 19, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000527 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M05", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000604 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M06", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000627 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M06", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000704 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14000727 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14001122 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M11", day: 22, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14001127 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M11", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14001222 = Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 22, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14010127 = Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 27, hour: 12, minute: 34, timeZone: "UTC", calendar });
+const date14010604 = Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M06", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar });
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.subtract(weeks1).toPlainDateTime(),
+  1400, 2, "M02", 26, 12, 34, 0, 0, 0, 0, "add 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.subtract(weeks1).toPlainDateTime(),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "add 1w with result on the last day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 23, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks1).toPlainDateTime(),
+  1401, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "add 1w with result on the first day of the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000627.subtract(weeks1).toPlainDateTime(),
+  1400, 7, "M07", 3, 12, 34, 0, 0, 0, 0, "add 1w in a 31-day month with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14000727.subtract(weeks1).toPlainDateTime(),
+  1400, 8, "M08", 4, 12, 34, 0, 0, 0, 0, "add 1w in a 30-day month with result in the next month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010127.subtract(weeks6).toPlainDateTime(),
+  1401, 3, "M03", 7, 12, 34, 0, 0, 0, 0, "add 6w with result in the same year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001222.subtract(weeks6).toPlainDateTime(),
+  1401, 2, "M02", 4, 12, 34, 0, 0, 0, 0, "add 6w with result in the next year",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14001127.subtract(weeks6).toPlainDateTime(),
+  1401, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 30 and 31 days",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  date14000627.subtract(weeks6).toPlainDateTime(),
+  1400, 8, "M08", 8, 12, 34, 0, 0, 0, 0, "add 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.subtract(years1weeks2).toPlainDateTime(),
+  1401, 1, "M01", 13, 12, 34, 0, 0, 0, 0, "add 1y 2w with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M10", day: 28, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months2weeks3).toPlainDateTime(),
+  1399, 1, "M01", 20, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M10", day: 31, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months2weeks3).toPlainDateTime(),
+  1399, 1, "M01", 21, 12, 34, 0, 0, 0, 0, "add 2mo 3w with result in the next year",
+  "ap", 1399);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000219.subtract(weeks1n).toPlainDateTime(),
+  1400, 2, "M02", 12, 12, 34, 0, 0, 0, 0, "subtract 1w",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M01", day: 8, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks1n).toPlainDateTime(),
+  1400, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the first day of the year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 7, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks1n).toPlainDateTime(),
+  1400, 12, "M12", 29, 12, 34, 0, 0, 0, 0, "subtract 1w with result on the last day of the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000704.subtract(weeks1n).toPlainDateTime(),
+  1400, 6, "M06", 28, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 31-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 3, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks1n).toPlainDateTime(),
+  1400, 11, "M11", 26, 12, 34, 0, 0, 0, 0, "subtract 1w with result in the previous 30-day month",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000604.subtract(weeks6n).toPlainDateTime(),
+  1400, 4, "M04", 24, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the same year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010127.subtract(weeks6n).toPlainDateTime(),
+  1400, 12, "M12", 14, 12, 34, 0, 0, 0, 0, "subtract 6w with result in the previous year",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 8, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks6n).toPlainDateTime(),
+  1400, 5, "M05", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 30 and 31 days",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M03", day: 8, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks6n).toPlainDateTime(),
+  1400, 1, "M01", 28, 12, 34, 0, 0, 0, 0, "subtract 6w crossing months of 31 and 31 days",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1402, monthCode: "M01", day: 5, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(years1weeks2n).toPlainDateTime(),
+  1400, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 1y 2w with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1398, monthCode: "M03", day: 2, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(months2weeks3n).toPlainDateTime(),
+  1397, 12, "M12", 10, 12, 34, 0, 0, 0, 0, "subtract 2mo 3w with result in the previous year",
+  "ap", 1397);
+
+// Days
+
+const days10 = new Temporal.Duration(0, 0, 0, -10);
+const days10n = new Temporal.Duration(0, 0, 0, 10);
+const weeks2days3 = new Temporal.Duration(0, 0, -2, -3);
+const weeks2days3n = new Temporal.Duration(0, 0, 2, 3);
+const years1months2days4 = new Temporal.Duration(-1, -2, 0, -4);
+const years1months2days4n = new Temporal.Duration(1, 2, 0, 4);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(days10).toPlainDateTime(),
+  1400, 7, "M07", 26, 12, 34, 0, 0, 0, 0, "add 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 26, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(days10).toPlainDateTime(),
+  1400, 8, "M08", 6, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M12", day: 26, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(days10).toPlainDateTime(),
+  1401, 1, "M01", 7, 12, 34, 0, 0, 0, 0, "add 10 days with result in the next year",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date13991228.subtract(weeks2days3).toPlainDateTime(),
+  1400, 1, "M01", 15, 12, 34, 0, 0, 0, 0, "add 2w 3d with result in the next year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(years1months2days4).toPlainDateTime(),
+  1401, 9, "M09", 20, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d",
+  "ap", 1401);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1399, monthCode: "M10", day: 20, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(years1months2days4).toPlainDateTime(),
+  1400, 12, "M12", 24, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M05", day: 26, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(years1months2days4).toPlainDateTime(),
+  1401, 7, "M07", 30, 12, 34, 0, 0, 0, 0, "add 1y 2mo 4d with result in a month following a 31-day month",
+  "ap", 1401);
+
+TemporalHelpers.assertPlainDateTime(
+  date14000716.subtract(days10n).toPlainDateTime(),
+  1400, 7, "M07", 6, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the same month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1400, monthCode: "M07", day: 6, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(days10n).toPlainDateTime(),
+  1400, 6, "M06", 27, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(days10n).toPlainDateTime(),
+  1400, 12, "M12", 23, 12, 34, 0, 0, 0, 0, "subtract 10 days with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M01", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(weeks2days3n).toPlainDateTime(),
+  1400, 12, "M12", 27, 12, 34, 0, 0, 0, 0, "subtract 2w 3d with result in the previous year",
+  "ap", 1400);
+
+TemporalHelpers.assertPlainDateTime(
+  date14010716.subtract(years1months2days4n).toPlainDateTime(),
+  1400, 5, "M05", 12, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 1401, monthCode: "M12", day: 4, hour: 12, minute: 34, timeZone: "UTC", calendar }).subtract(years1months2days4n).toPlainDateTime(),
+  1400, 9, "M09", 30, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 30-day month",
+  "ap", 1400);
+TemporalHelpers.assertPlainDateTime(
+  date14010604.subtract(years1months2days4n).toPlainDateTime(),
+  1400, 3, "M03", 31, 12, 34, 0, 0, 0, 0, "subtract 1y 2mo 4d with result in a 31-day month",
+  "ap", 1400);