Maryland Math 4.NOS.B.3.a
The Standard
- 4.NOS.B.3
- Fluently add and subtract multi-digit whole numbers within 1,000,000.
Apply estimation strategies to estimate sums and differences.
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 round numbers to estimate sums and differences. They show the rounded numbers they used and explain why the result is reasonable.
What Mastery Looks Like
- For 487 + 316, a student uses 500 + 300 to estimate 800. For 903 − 487, they use 900 − 500 to estimate 400.
Common Misconceptions
- Students may round 487 to 400 instead of 500 when rounding to the nearest hundred. They may treat an estimate as an exact answer or add when the problem asks for a difference.
How to Assess It
- Exit ticket: Estimate 638 + 275 and 904 − 489 by rounding to the nearest hundred. Write the rounded equation for each.
Lesson moves
Ways to Teach It
Give pairs base-ten blocks to build 368 and 241, then have them round each number to estimate the total.
Ask, "Is 498 + 301 closer to 700 or 800? Show the rounded numbers that support your answer."
Put 472 + 318, 615 − 289, and 783 + 194 on cards; partners match each to a nearest-hundred estimate.
Show two field-trip bus quotes, $487 and $312; students round to hundreds to estimate how much more one costs.
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Printable 4.NOS.B.3.a Worksheet
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