Maryland Math 3.NOS.D.7
Standard Cluster
Fluently add and subtract within 1,000. Use computational strategies efficiently (e.g., decomposition, partials sums, compensation, make ten/hundred/thousand) to add and subtract. Use properties of operations, and/or the inverse relationship between addition and subtraction. Determine and explain when a strategy is most efficient.
Maryland College and Career Ready Standards for Mathematics (2025) · USE PLACE VALUE UNDERSTANDING AND PROPERTIES OF OPERATIONS TO PERFORM MULTI-DIGIT ARITHMETIC.
Cluster contents
Standards in This Cluster
3.NOS.D.7 is a cluster heading. These are the individual standards under it.
- 3.NOS.D.7.a
Use computational strategies efficiently (e.g., decomposition, partials sums, compensation, make ten/hundred/thousand) to add and subtract.
- 3.NOS.D.7.b
Use properties of operations, and/or the inverse relationship between addition and subtraction.
- 3.NOS.D.7.c
Determine and explain when a strategy is most efficient.
Teacher's field guide
What This Cluster Means
What Students Need to Do
- Students add and subtract within 1,000 by breaking numbers apart, regrouping addends, or making a friendly number. They choose a method that fits the numbers and explain why.
What Mastery Looks Like
- A student solves 398 + 247 as 400 + 245 and 602 − 298 as 604 − 300. They explain why those changes make the work easier and check an answer with the opposite operation.
Common Misconceptions
- Students may change only one number when adjusting a subtraction problem, which changes the difference. Others mix up hundreds and tens in partial sums or try to subtract through a zero without regrouping.
How to Assess It
- Exit ticket: Solve 602 − 298. Explain why you chose your method, then check your answer with addition.
Lesson moves
Ways to Teach It
Use base-ten blocks to show 452 − 178; trade a hundred and a ten, then write matching subtraction steps.
Ask students whether making 400 or using partial sums is quicker for 398 + 247, and have them explain their choice.
Give pairs cards labeled 298, 304, 398, 402, 602, and 745; draw two, subtract smaller from larger, then verify with addition.
Post a goal of 1,000 library books and 683 already collected; students find how many remain and explain their method.
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Printable 3.NOS.D.7 Worksheet
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Related Standards
- 6.NOS.B.3
Fluently multiply and divide multi-digit decimals to the thousandths in context.
- 4.NOS.B.3
Fluently add and subtract multi-digit whole numbers within 1,000,000.
- 2.NOS.C.9
Add and subtract within 1000, recognizing that when adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones ...
- 2.NOS.C.8
Fluently add and subtract within 100.
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