Maryland Math 3.NOS.D.7.b
The Standard
- 3.NOS.D.7
- Fluently add and subtract within 1,000.
Use properties of operations, and/or the inverse relationship between addition and subtraction.
Maryland College and Career Ready Standards for Mathematics (2025) · USE PLACE VALUE UNDERSTANDING AND PROPERTIES OF OPERATIONS TO PERFORM MULTI-DIGIT ARITHMETIC.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students rearrange or group addends to make addition easier. They use addition to check subtraction and subtraction to check addition. They explain why their steps work.
What Mastery Looks Like
- A student can group hundreds, tens, and ones to solve 238 + 157 = 395, then check with 395 − 157 = 238. They know they can switch addends, but cannot switch the numbers in a subtraction problem.
Common Misconceptions
- Some students think 72 − 25 gives the same answer as 25 − 72. Others try to check 438 − 176 by adding 438 + 176, rather than adding the difference to 176.
How to Assess It
- Exit ticket: Solve 346 + 128 by regrouping the addends. Write a subtraction equation that checks your answer, and explain how it checks.
Lesson moves
Ways to Teach It
Build 236 + 145 with base-ten blocks, then remove 145 from the total to check the sum.
Write 48 + 27 = 27 + 48 and 48 − 27 ≠ 27 − 48; ask partners to explain the difference.
Give pairs an addition fact card, such as 321 + 146 = 467; have them race to write both related subtraction facts.
Tell students a library had 275 books and checked out 138; have them find how many remain and check with addition.
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Printable 3.NOS.D.7.b Worksheet
A ready-to-print activity worksheet aligned to 3.NOS.D.7.b, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- 1.NOS.E.10.c
Use properties of operations, and/or the inverse relationship between addition and subtraction to add.
- 2.NOS.C.8.b
Use properties of operations, and the inverse relationship between addition and subtraction to add and subtract.
- 2.NOS.C.9.c
Use properties of operations, and/or the relationship between addition and subtraction to add and subtract.
- 1.NOS.E.12.b
Use counting strategies, properties of operations, and/or the inverse relationship between addition and subtraction to subtract.
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