4th Grade Estimating Sums and Differences by Rounding Worksheet
Round each number first, then add or subtract to estimate — a fast way to check if an answer is reasonable.
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- Review
- Test Prep
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- Grade
- 4th Grade
- Subject
- Math
- Skill
- Rounding
- Topic
- estimating sums and differences
- Difficulty
- Standard
- Time
- 15 minutes
- Pages
- 2 (incl. answer key)
- Format
- Printable PDF (US Letter)
- Answer key
- Included
- Best for
- homework, review, test prep, tutoring
Worksheet details
What This Worksheet Practices
Students will estimate sums and differences by rounding each number to the nearest ten or hundred.
- Rounding to the nearest 10 or 100
- Estimating sums and differences
- Judging whether an exact answer is reasonable
Worksheet Preview
Estimate first, then check
Estimation answers a different question than exact arithmetic: “about how much?” By rounding each number before adding or subtracting, students get a quick, in-their-head ballpark they can use to check whether an exact answer is reasonable. If you compute 38 + 41 and get 791, your estimate of 80 tells you something went wrong.
How to use it
The key habit is round first, compute second. Decide the place (nearest 10 or 100), round each number, then add or subtract the rounded values. Tie it back to the exact answer: “Is your real answer close to the estimate?” This applies the skill from rounding to the nearest 10 and 100.
👩🏫 Teacher note
Round BEFORE computing. Estimation is for checking reasonableness, so connect it back: 'Is the exact answer close to your estimate?'
🏠 Parent note
Round each number to the nearest ten (or hundred) first, then add the rounded numbers.
Common Mistakes to Watch For
- Rounding after adding instead of before
- Rounding to the wrong place
Answer Key
Each answer shows the rounded numbers and the estimate.
⬇ Download Answer Key (PDF)Related Worksheets
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