diff --git a/test/intl402/Temporal/PlainDate/prototype/add/basic-hebrew.js b/test/intl402/Temporal/PlainDate/prototype/add/basic-hebrew.js
index 0355907a06..2853031bfb 100644
--- a/test/intl402/Temporal/PlainDate/prototype/add/basic-hebrew.js
+++ b/test/intl402/Temporal/PlainDate/prototype/add/basic-hebrew.js
@@ -13,15 +13,193 @@ const options = { overflow: "reject" };
 
 // Years
 
+const years1 = new Temporal.Duration(1);
+const years1n = new Temporal.Duration(-1);
+const years5 = new Temporal.Duration(5);
+const years5n = new Temporal.Duration(-5);
+
+const date577902 = Temporal.PlainDate.from({ year: 5779, monthCode: "M02", day: 1, calendar }, options);
+const date578402 = Temporal.PlainDate.from({ year: 5784, monthCode: "M02", day: 29, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  date577902.add(years1),
+  5780, 2, "M02", 1, "Adding 1 year to day 1 of a month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.add(years1),
+  5785, 2, "M02", 29, "Adding 1 year to day 29 of a month",
+  "am", 5785
+);
+
+TemporalHelpers.assertPlainDate(
+  date577902.add(years5),
+  5784, 2, "M02", 1, "Adding 5 years to day 1 of a month",
+  "am", 5784
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.add(years5),
+  5789, 2, "M02", 29, "Adding 5 years to day 29 of a month",
+  "am", 5789
+);
+
+TemporalHelpers.assertPlainDate(
+  date577902.add(years1n),
+  5778, 2, "M02", 1, "Subtracting 1 year from day 1 of a month",
+  "am", 5778
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.add(years1n),
+  5783, 2, "M02", 29, "Subtracting 1 year from day 29 of a month",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDate(
+  date577902.add(years5n),
+  5774, 2, "M02", 1, "Subtracting 5 years from day 1 of a month",
+  "am", 5774
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.add(years5n),
+  5779, 2, "M02", 29, "Subtracting 5 years from day 29 of a month",
+  "am", 5779
+);
+
 // Months
 
+const months1 = new Temporal.Duration(0, 1);
+const months1n = new Temporal.Duration(0, -1);
+const months4 = new Temporal.Duration(0, 4);
+const months4n = new Temporal.Duration(0, -4);
+
+const date578001 = Temporal.PlainDate.from({ year: 5780, monthCode: "M01", day: 1, calendar }, options);
+const date578006 = Temporal.PlainDate.from({ year: 5780, monthCode: "M06", day: 1, calendar }, options);
+const date578011 = Temporal.PlainDate.from({ year: 5780, monthCode: "M11", day: 1, calendar }, options);
+const date578012 = Temporal.PlainDate.from({ year: 5780, monthCode: "M12", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  date578011.add(months1),
+  5780, 12, "M12", 1, "Adding 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578012.add(months1),
+  5781, 1, "M01", 1, "Adding 1 month, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDate(
+  date578006.add(months4),
+  5780, 10, "M10", 1, "Adding 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578012.add(months4),
+  5781, 4, "M04", 1, "Adding 4 months, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDate(
+  date578011.add(months1n),
+  5780, 10, "M10", 1, "Subtracting 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578001.add(months1n),
+  5779, 13, "M12", 1, "Subtracting 1 month, with result in previous year",
+  "am", 5779
+);
+
+TemporalHelpers.assertPlainDate(
+  date578006.add(months4n),
+  5780, 2, "M02", 1, "Subtracting 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578001.add(months4n),
+  5779, 10, "M09", 1, "Subtracting 4 months, with result in previous year",
+  "am", 5779
+);
+
 // Weeks
 
+const months2weeks3 = new Temporal.Duration(0, /* months = */ 2, /* weeks = */ 3);
+const months2weeks3n = new Temporal.Duration(0, -2, -3);
+
+const date578201 = Temporal.PlainDate.from({ year: 5782, monthCode: "M01", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  date578201.add(months2weeks3),
+  5782, 3, "M03", 22, "add 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 5782, monthCode: "M12", day: 29, calendar }, options).add(months2weeks3),
+  5783, 3, "M03", 20, "add 2 months 3 weeks from end of year to next year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 5782, monthCode: "M10", day: 1, calendar }, options).add(months2weeks3n),
+  5782, 8, "M07", 10, "subtract 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDate(
+  date578201.add(months2weeks3n),
+  5781, 10, "M10", 9, "subtract 2 months 3 weeks from beginning of year to previous year",
+  "am", 5781
+);
+
+
 // Days
 
 const days10 = new Temporal.Duration(0, 0, 0, /* days = */ 10);
+const days10n = new Temporal.Duration(0, 0, 0, -10);
+
+const date57800129 = Temporal.PlainDate.from({ year: 5780, monthCode: "M01", day: 29, calendar }, options);
 
 TemporalHelpers.assertPlainDate(
-  Temporal.PlainDate.from({ year: 5785, monthCode: "M01", day: 1, calendar }, options).add(days10),
-  5785, 1, "M01", 11, "adding 10 days", "am", 5785
+  date578201.add(days10),
+  5782, 1, "M01", 11, "add 10 days, ending in same month",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDate(
+  date57800129.add(days10),
+  5780, 2, "M02", 9, "add 10 days, ending in following month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 5782, monthCode: "M12", day: 29, calendar }, options).add(days10),
+  5783, 1, "M01", 10, "add 10 days, ending in following year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDate(
+  date57800129.add(days10n),
+  5780, 1, "M01", 19, "subtract 10 days, ending in same month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578006.add(days10n),
+  5780, 5, "M05", 21, "subtract 10 days, ending in previous month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578201.add(days10n),
+  5781, 12, "M12", 20, "subtract 10 days, ending in previous year",
+  "am", 5781
 );
diff --git a/test/intl402/Temporal/PlainDate/prototype/subtract/basic-hebrew.js b/test/intl402/Temporal/PlainDate/prototype/subtract/basic-hebrew.js
index 78b9ee99dd..c883326bdc 100644
--- a/test/intl402/Temporal/PlainDate/prototype/subtract/basic-hebrew.js
+++ b/test/intl402/Temporal/PlainDate/prototype/subtract/basic-hebrew.js
@@ -13,15 +13,193 @@ const options = { overflow: "reject" };
 
 // Years
 
+const years1 = new Temporal.Duration(-1);
+const years1n = new Temporal.Duration(1);
+const years5 = new Temporal.Duration(-5);
+const years5n = new Temporal.Duration(5);
+
+const date577902 = Temporal.PlainDate.from({ year: 5779, monthCode: "M02", day: 1, calendar }, options);
+const date578402 = Temporal.PlainDate.from({ year: 5784, monthCode: "M02", day: 29, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  date577902.subtract(years1),
+  5780, 2, "M02", 1, "Adding 1 year to day 1 of a month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.subtract(years1),
+  5785, 2, "M02", 29, "Adding 1 year to day 29 of a month",
+  "am", 5785
+);
+
+TemporalHelpers.assertPlainDate(
+  date577902.subtract(years5),
+  5784, 2, "M02", 1, "Adding 5 years to day 1 of a month",
+  "am", 5784
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.subtract(years5),
+  5789, 2, "M02", 29, "Adding 5 years to day 29 of a month",
+  "am", 5789
+);
+
+TemporalHelpers.assertPlainDate(
+  date577902.subtract(years1n),
+  5778, 2, "M02", 1, "Subtracting 1 year from day 1 of a month",
+  "am", 5778
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.subtract(years1n),
+  5783, 2, "M02", 29, "Subtracting 1 year from day 29 of a month",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDate(
+  date577902.subtract(years5n),
+  5774, 2, "M02", 1, "Subtracting 5 years from day 1 of a month",
+  "am", 5774
+);
+
+TemporalHelpers.assertPlainDate(
+  date578402.subtract(years5n),
+  5779, 2, "M02", 29, "Subtracting 5 years from day 29 of a month",
+  "am", 5779
+);
+
 // Months
 
+const months1 = new Temporal.Duration(0, -1);
+const months1n = new Temporal.Duration(0, 1);
+const months4 = new Temporal.Duration(0, -4);
+const months4n = new Temporal.Duration(0, 4);
+
+const date578001 = Temporal.PlainDate.from({ year: 5780, monthCode: "M01", day: 1, calendar }, options);
+const date578006 = Temporal.PlainDate.from({ year: 5780, monthCode: "M06", day: 1, calendar }, options);
+const date578011 = Temporal.PlainDate.from({ year: 5780, monthCode: "M11", day: 1, calendar }, options);
+const date578012 = Temporal.PlainDate.from({ year: 5780, monthCode: "M12", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  date578011.subtract(months1),
+  5780, 12, "M12", 1, "Adding 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578012.subtract(months1),
+  5781, 1, "M01", 1, "Adding 1 month, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDate(
+  date578006.subtract(months4),
+  5780, 10, "M10", 1, "Adding 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578012.subtract(months4),
+  5781, 4, "M04", 1, "Adding 4 months, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDate(
+  date578011.subtract(months1n),
+  5780, 10, "M10", 1, "Subtracting 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578001.subtract(months1n),
+  5779, 13, "M12", 1, "Subtracting 1 month, with result in previous year",
+  "am", 5779
+);
+
+TemporalHelpers.assertPlainDate(
+  date578006.subtract(months4n),
+  5780, 2, "M02", 1, "Subtracting 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578001.subtract(months4n),
+  5779, 10, "M09", 1, "Subtracting 4 months, with result in previous year",
+  "am", 5779
+);
+
 // Weeks
 
+const months2weeks3 = new Temporal.Duration(0, /* months = */ -2, /* weeks = */ -3);
+const months2weeks3n = new Temporal.Duration(0, 2, 3);
+
+const date578201 = Temporal.PlainDate.from({ year: 5782, monthCode: "M01", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  date578201.subtract(months2weeks3),
+  5782, 3, "M03", 22, "add 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 5782, monthCode: "M12", day: 29, calendar }, options).subtract(months2weeks3),
+  5783, 3, "M03", 20, "add 2 months 3 weeks from end of year to next year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 5782, monthCode: "M10", day: 1, calendar }, options).subtract(months2weeks3n),
+  5782, 8, "M07", 10, "subtract 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDate(
+  date578201.subtract(months2weeks3n),
+  5781, 10, "M10", 9, "subtract 2 months 3 weeks from beginning of year to previous year",
+  "am", 5781
+);
+
+
 // Days
 
 const days10 = new Temporal.Duration(0, 0, 0, /* days = */ -10);
+const days10n = new Temporal.Duration(0, 0, 0, 10);
+
+const date57800129 = Temporal.PlainDate.from({ year: 5780, monthCode: "M01", day: 29, calendar }, options);
 
 TemporalHelpers.assertPlainDate(
-  Temporal.PlainDate.from({ year: 5785, monthCode: "M01", day: 1, calendar }, options).subtract(days10),
-  5785, 1, "M01", 11, "adding 10 days", "am", 5785
+  date578201.subtract(days10),
+  5782, 1, "M01", 11, "add 10 days, ending in same month",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDate(
+  date57800129.subtract(days10),
+  5780, 2, "M02", 9, "add 10 days, ending in following month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  Temporal.PlainDate.from({ year: 5782, monthCode: "M12", day: 29, calendar }, options).subtract(days10),
+  5783, 1, "M01", 10, "add 10 days, ending in following year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDate(
+  date57800129.subtract(days10n),
+  5780, 1, "M01", 19, "subtract 10 days, ending in same month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578006.subtract(days10n),
+  5780, 5, "M05", 21, "subtract 10 days, ending in previous month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDate(
+  date578201.subtract(days10n),
+  5781, 12, "M12", 20, "subtract 10 days, ending in previous year",
+  "am", 5781
 );
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/add/basic-hebrew.js b/test/intl402/Temporal/PlainDateTime/prototype/add/basic-hebrew.js
index 62dd3012bc..d494d5e86e 100644
--- a/test/intl402/Temporal/PlainDateTime/prototype/add/basic-hebrew.js
+++ b/test/intl402/Temporal/PlainDateTime/prototype/add/basic-hebrew.js
@@ -13,15 +13,193 @@ const options = { overflow: "reject" };
 
 // Years
 
+const years1 = new Temporal.Duration(1);
+const years1n = new Temporal.Duration(-1);
+const years5 = new Temporal.Duration(5);
+const years5n = new Temporal.Duration(-5);
+
+const date577902 = Temporal.PlainDateTime.from({ year: 5779, monthCode: "M02", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578402 = Temporal.PlainDateTime.from({ year: 5784, monthCode: "M02", day: 29, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years1),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 1 of a month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years1),
+  5785, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 29 of a month",
+  "am", 5785
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years5),
+  5784, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 1 of a month",
+  "am", 5784
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years5),
+  5789, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 29 of a month",
+  "am", 5789
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years1n),
+  5778, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 1 of a month",
+  "am", 5778
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years1n),
+  5783, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 29 of a month",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years5n),
+  5774, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 1 of a month",
+  "am", 5774
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years5n),
+  5779, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 29 of a month",
+  "am", 5779
+);
+
 // Months
 
+const months1 = new Temporal.Duration(0, 1);
+const months1n = new Temporal.Duration(0, -1);
+const months4 = new Temporal.Duration(0, 4);
+const months4n = new Temporal.Duration(0, -4);
+
+const date578001 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M01", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578006 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M06", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578011 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M11", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578012 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M12", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.add(months1),
+  5780, 12, "M12", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.add(months1),
+  5781, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.add(months4),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.add(months4),
+  5781, 4, "M04", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.add(months1n),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.add(months1n),
+  5779, 13, "M12", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in previous year",
+  "am", 5779
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.add(months4n),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.add(months4n),
+  5779, 10, "M09", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in previous year",
+  "am", 5779
+);
+
 // Weeks
 
+const months2weeks3 = new Temporal.Duration(0, /* months = */ 2, /* weeks = */ 3);
+const months2weeks3n = new Temporal.Duration(0, -2, -3);
+
+const date578201 = Temporal.PlainDateTime.from({ year: 5782, monthCode: "M01", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.add(months2weeks3),
+  5782, 3, "M03", 22, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, calendar }, options).add(months2weeks3),
+  5783, 3, "M03", 20, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks from end of year to next year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 5782, monthCode: "M10", day: 1, hour: 12, minute: 34, calendar }, options).add(months2weeks3n),
+  5782, 8, "M07", 10, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.add(months2weeks3n),
+  5781, 10, "M10", 9, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks from beginning of year to previous year",
+  "am", 5781
+);
+
+
 // Days
 
 const days10 = new Temporal.Duration(0, 0, 0, /* days = */ 10);
+const days10n = new Temporal.Duration(0, 0, 0, -10);
+
+const date57800129 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M01", day: 29, hour: 12, minute: 34, calendar }, options);
 
 TemporalHelpers.assertPlainDateTime(
-  Temporal.PlainDateTime.from({ year: 5785, monthCode: "M01", day: 1, hour: 12, minute: 34, calendar }, options).add(days10),
-  5785, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "adding 10 days", "am", 5785
+  date578201.add(days10),
+  5782, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "add 10 days, ending in same month",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.add(days10),
+  5780, 2, "M02", 9, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, calendar }, options).add(days10),
+  5783, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.add(days10n),
+  5780, 1, "M01", 19, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in same month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.add(days10n),
+  5780, 5, "M05", 21, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.add(days10n),
+  5781, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous year",
+  "am", 5781
 );
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-hebrew.js b/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-hebrew.js
index 119a8f9990..b1bc1249d5 100644
--- a/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-hebrew.js
+++ b/test/intl402/Temporal/PlainDateTime/prototype/subtract/basic-hebrew.js
@@ -13,15 +13,193 @@ const options = { overflow: "reject" };
 
 // Years
 
+const years1 = new Temporal.Duration(-1);
+const years1n = new Temporal.Duration(1);
+const years5 = new Temporal.Duration(-5);
+const years5n = new Temporal.Duration(5);
+
+const date577902 = Temporal.PlainDateTime.from({ year: 5779, monthCode: "M02", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578402 = Temporal.PlainDateTime.from({ year: 5784, monthCode: "M02", day: 29, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years1),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 1 of a month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years1),
+  5785, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 29 of a month",
+  "am", 5785
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years5),
+  5784, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 1 of a month",
+  "am", 5784
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years5),
+  5789, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 29 of a month",
+  "am", 5789
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years1n),
+  5778, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 1 of a month",
+  "am", 5778
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years1n),
+  5783, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 29 of a month",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years5n),
+  5774, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 1 of a month",
+  "am", 5774
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years5n),
+  5779, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 29 of a month",
+  "am", 5779
+);
+
 // Months
 
+const months1 = new Temporal.Duration(0, -1);
+const months1n = new Temporal.Duration(0, 1);
+const months4 = new Temporal.Duration(0, -4);
+const months4n = new Temporal.Duration(0, 4);
+
+const date578001 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M01", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578006 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M06", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578011 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M11", day: 1, hour: 12, minute: 34, calendar }, options);
+const date578012 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M12", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.subtract(months1),
+  5780, 12, "M12", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.subtract(months1),
+  5781, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.subtract(months4),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.subtract(months4),
+  5781, 4, "M04", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.subtract(months1n),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.subtract(months1n),
+  5779, 13, "M12", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in previous year",
+  "am", 5779
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.subtract(months4n),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.subtract(months4n),
+  5779, 10, "M09", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in previous year",
+  "am", 5779
+);
+
 // Weeks
 
+const months2weeks3 = new Temporal.Duration(0, /* months = */ -2, /* weeks = */ -3);
+const months2weeks3n = new Temporal.Duration(0, 2, 3);
+
+const date578201 = Temporal.PlainDateTime.from({ year: 5782, monthCode: "M01", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.subtract(months2weeks3),
+  5782, 3, "M03", 22, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, calendar }, options).subtract(months2weeks3),
+  5783, 3, "M03", 20, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks from end of year to next year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 5782, monthCode: "M10", day: 1, hour: 12, minute: 34, calendar }, options).subtract(months2weeks3n),
+  5782, 8, "M07", 10, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.subtract(months2weeks3n),
+  5781, 10, "M10", 9, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks from beginning of year to previous year",
+  "am", 5781
+);
+
+
 // Days
 
 const days10 = new Temporal.Duration(0, 0, 0, /* days = */ -10);
+const days10n = new Temporal.Duration(0, 0, 0, 10);
+
+const date57800129 = Temporal.PlainDateTime.from({ year: 5780, monthCode: "M01", day: 29, hour: 12, minute: 34, calendar }, options);
 
 TemporalHelpers.assertPlainDateTime(
-  Temporal.PlainDateTime.from({ year: 5785, monthCode: "M01", day: 1, hour: 12, minute: 34, calendar }, options).subtract(days10),
-  5785, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "adding 10 days", "am", 5785
+  date578201.subtract(days10),
+  5782, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "add 10 days, ending in same month",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.subtract(days10),
+  5780, 2, "M02", 9, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.PlainDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, calendar }, options).subtract(days10),
+  5783, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.subtract(days10n),
+  5780, 1, "M01", 19, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in same month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.subtract(days10n),
+  5780, 5, "M05", 21, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.subtract(days10n),
+  5781, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous year",
+  "am", 5781
 );
diff --git a/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-hebrew.js b/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-hebrew.js
index 712f2e8ef1..62fb0ad294 100644
--- a/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-hebrew.js
+++ b/test/intl402/Temporal/ZonedDateTime/prototype/add/basic-hebrew.js
@@ -13,15 +13,193 @@ const options = { overflow: "reject" };
 
 // Years
 
+const years1 = new Temporal.Duration(1);
+const years1n = new Temporal.Duration(-1);
+const years5 = new Temporal.Duration(5);
+const years5n = new Temporal.Duration(-5);
+
+const date577902 = Temporal.ZonedDateTime.from({ year: 5779, monthCode: "M02", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578402 = Temporal.ZonedDateTime.from({ year: 5784, monthCode: "M02", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years1).toPlainDateTime(),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 1 of a month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years1).toPlainDateTime(),
+  5785, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 29 of a month",
+  "am", 5785
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years5).toPlainDateTime(),
+  5784, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 1 of a month",
+  "am", 5784
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years5).toPlainDateTime(),
+  5789, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 29 of a month",
+  "am", 5789
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years1n).toPlainDateTime(),
+  5778, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 1 of a month",
+  "am", 5778
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years1n).toPlainDateTime(),
+  5783, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 29 of a month",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.add(years5n).toPlainDateTime(),
+  5774, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 1 of a month",
+  "am", 5774
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.add(years5n).toPlainDateTime(),
+  5779, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 29 of a month",
+  "am", 5779
+);
+
 // Months
 
+const months1 = new Temporal.Duration(0, 1);
+const months1n = new Temporal.Duration(0, -1);
+const months4 = new Temporal.Duration(0, 4);
+const months4n = new Temporal.Duration(0, -4);
+
+const date578001 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M01", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578006 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M06", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578011 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M11", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578012 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M12", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.add(months1).toPlainDateTime(),
+  5780, 12, "M12", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.add(months1).toPlainDateTime(),
+  5781, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.add(months4).toPlainDateTime(),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.add(months4).toPlainDateTime(),
+  5781, 4, "M04", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.add(months1n).toPlainDateTime(),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.add(months1n).toPlainDateTime(),
+  5779, 13, "M12", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in previous year",
+  "am", 5779
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.add(months4n).toPlainDateTime(),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.add(months4n).toPlainDateTime(),
+  5779, 10, "M09", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in previous year",
+  "am", 5779
+);
+
 // Weeks
 
+const months2weeks3 = new Temporal.Duration(0, /* months = */ 2, /* weeks = */ 3);
+const months2weeks3n = new Temporal.Duration(0, -2, -3);
+
+const date578201 = Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M01", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.add(months2weeks3).toPlainDateTime(),
+  5782, 3, "M03", 22, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).add(months2weeks3).toPlainDateTime(),
+  5783, 3, "M03", 20, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks from end of year to next year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M10", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).add(months2weeks3n).toPlainDateTime(),
+  5782, 8, "M07", 10, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.add(months2weeks3n).toPlainDateTime(),
+  5781, 10, "M10", 9, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks from beginning of year to previous year",
+  "am", 5781
+);
+
+
 // Days
 
 const days10 = new Temporal.Duration(0, 0, 0, /* days = */ 10);
+const days10n = new Temporal.Duration(0, 0, 0, -10);
+
+const date57800129 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M01", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
 
 TemporalHelpers.assertPlainDateTime(
-  Temporal.ZonedDateTime.from({ year: 5785, monthCode: "M01", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).add(days10).toPlainDateTime(),
-  5785, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "adding 10 days", "am", 5785
+  date578201.add(days10).toPlainDateTime(),
+  5782, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "add 10 days, ending in same month",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.add(days10).toPlainDateTime(),
+  5780, 2, "M02", 9, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).add(days10).toPlainDateTime(),
+  5783, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.add(days10n).toPlainDateTime(),
+  5780, 1, "M01", 19, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in same month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.add(days10n).toPlainDateTime(),
+  5780, 5, "M05", 21, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.add(days10n).toPlainDateTime(),
+  5781, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous year",
+  "am", 5781
 );
diff --git a/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-hebrew.js b/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-hebrew.js
index 8fcf47ec77..449c9dd816 100644
--- a/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-hebrew.js
+++ b/test/intl402/Temporal/ZonedDateTime/prototype/subtract/basic-hebrew.js
@@ -13,15 +13,193 @@ const options = { overflow: "reject" };
 
 // Years
 
+const years1 = new Temporal.Duration(-1);
+const years1n = new Temporal.Duration(1);
+const years5 = new Temporal.Duration(-5);
+const years5n = new Temporal.Duration(5);
+
+const date577902 = Temporal.ZonedDateTime.from({ year: 5779, monthCode: "M02", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578402 = Temporal.ZonedDateTime.from({ year: 5784, monthCode: "M02", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years1).toPlainDateTime(),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 1 of a month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years1).toPlainDateTime(),
+  5785, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 1 year to day 29 of a month",
+  "am", 5785
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years5).toPlainDateTime(),
+  5784, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 1 of a month",
+  "am", 5784
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years5).toPlainDateTime(),
+  5789, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Adding 5 years to day 29 of a month",
+  "am", 5789
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years1n).toPlainDateTime(),
+  5778, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 1 of a month",
+  "am", 5778
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years1n).toPlainDateTime(),
+  5783, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from day 29 of a month",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date577902.subtract(years5n).toPlainDateTime(),
+  5774, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 1 of a month",
+  "am", 5774
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578402.subtract(years5n).toPlainDateTime(),
+  5779, 2, "M02", 29, 12, 34, 0, 0, 0, 0, "Subtracting 5 years from day 29 of a month",
+  "am", 5779
+);
+
 // Months
 
+const months1 = new Temporal.Duration(0, -1);
+const months1n = new Temporal.Duration(0, 1);
+const months4 = new Temporal.Duration(0, -4);
+const months4n = new Temporal.Duration(0, 4);
+
+const date578001 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M01", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578006 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M06", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578011 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M11", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+const date578012 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M12", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.subtract(months1).toPlainDateTime(),
+  5780, 12, "M12", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.subtract(months1).toPlainDateTime(),
+  5781, 1, "M01", 1, 12, 34, 0, 0, 0, 0, "Adding 1 month, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.subtract(months4).toPlainDateTime(),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578012.subtract(months4).toPlainDateTime(),
+  5781, 4, "M04", 1, 12, 34, 0, 0, 0, 0, "Adding 4 months, with result in next year",
+  "am", 5781
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578011.subtract(months1n).toPlainDateTime(),
+  5780, 10, "M10", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.subtract(months1n).toPlainDateTime(),
+  5779, 13, "M12", 1, 12, 34, 0, 0, 0, 0, "Subtracting 1 month, with result in previous year",
+  "am", 5779
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.subtract(months4n).toPlainDateTime(),
+  5780, 2, "M02", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in same year",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578001.subtract(months4n).toPlainDateTime(),
+  5779, 10, "M09", 1, 12, 34, 0, 0, 0, 0, "Subtracting 4 months, with result in previous year",
+  "am", 5779
+);
+
 // Weeks
 
+const months2weeks3 = new Temporal.Duration(0, /* months = */ -2, /* weeks = */ -3);
+const months2weeks3n = new Temporal.Duration(0, 2, 3);
+
+const date578201 = Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M01", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.subtract(months2weeks3).toPlainDateTime(),
+  5782, 3, "M03", 22, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).subtract(months2weeks3).toPlainDateTime(),
+  5783, 3, "M03", 20, 12, 34, 0, 0, 0, 0, "add 2 months 3 weeks from end of year to next year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M10", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).subtract(months2weeks3n).toPlainDateTime(),
+  5782, 8, "M07", 10, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks, ending in same year",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.subtract(months2weeks3n).toPlainDateTime(),
+  5781, 10, "M10", 9, 12, 34, 0, 0, 0, 0, "subtract 2 months 3 weeks from beginning of year to previous year",
+  "am", 5781
+);
+
+
 // Days
 
 const days10 = new Temporal.Duration(0, 0, 0, /* days = */ -10);
+const days10n = new Temporal.Duration(0, 0, 0, 10);
+
+const date57800129 = Temporal.ZonedDateTime.from({ year: 5780, monthCode: "M01", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
 
 TemporalHelpers.assertPlainDateTime(
-  Temporal.ZonedDateTime.from({ year: 5785, monthCode: "M01", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).subtract(days10).toPlainDateTime(),
-  5785, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "adding 10 days", "am", 5785
+  date578201.subtract(days10).toPlainDateTime(),
+  5782, 1, "M01", 11, 12, 34, 0, 0, 0, 0, "add 10 days, ending in same month",
+  "am", 5782
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.subtract(days10).toPlainDateTime(),
+  5780, 2, "M02", 9, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  Temporal.ZonedDateTime.from({ year: 5782, monthCode: "M12", day: 29, hour: 12, minute: 34, timeZone: "UTC", calendar }, options).subtract(days10).toPlainDateTime(),
+  5783, 1, "M01", 10, 12, 34, 0, 0, 0, 0, "add 10 days, ending in following year",
+  "am", 5783
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date57800129.subtract(days10n).toPlainDateTime(),
+  5780, 1, "M01", 19, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in same month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578006.subtract(days10n).toPlainDateTime(),
+  5780, 5, "M05", 21, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous month",
+  "am", 5780
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date578201.subtract(days10n).toPlainDateTime(),
+  5781, 12, "M12", 20, 12, 34, 0, 0, 0, 0, "subtract 10 days, ending in previous year",
+  "am", 5781
 );