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Estimating Sums and Differences - Worksheet 9 - 3rd Grade

Hard

Practice estimating sums and differences using explicit place-value reasoning.

hard: Use another set to practice explaining and checking your answers.

23 problems · 10-15 minutes · Skills: estimation, rounding

About This Worksheet

This hard-level worksheet contains 23 problems designed for 3rd Grade students practicing estimating sums and differences. Hard worksheets feature challenging problems including multi-step questions, missing values, and real-world applications to push students further.

Recognize digits and read a place-value chart.

  • Practice estimating sums and differences using explicit place-value reasoning.
  • Check your result using the method in the example before moving to the next question.

How to Solve: Worked Example

Example Problem: Estimate 365 + 266 by first rounding each number to the nearest 10.
Solution Steps:
  1. 365 rounds to 370; 266 rounds to 270.
  2. Use the rounded values in the operation.
Answer: 640
Tip: Check your result using the method in the example before moving to the next question.
1
Estimate 983 + 100 by first rounding each number to the nearest 10.
2
Estimate 896 − 300 by first rounding each number to the nearest 10.
3
Estimate 910 + 892 by first rounding each number to the nearest 10.
4
Estimate 738 − 155 by first rounding each number to the nearest 10.
5
Estimate 663 + 164 by first rounding each number to the nearest 10.
6
Estimate 903 − 489 by first rounding each number to the nearest 10.
7
Estimate 564 + 439 by first rounding each number to the nearest 10.
8
Estimate 668 − 476 by first rounding each number to the nearest 10.
9
Estimate 937 + 610 by first rounding each number to the nearest 10.
10
Estimate 895 − 156 by first rounding each number to the nearest 10.
11
Estimate 842 + 668 by first rounding each number to the nearest 10.
12
Estimate 701 − 198 by first rounding each number to the nearest 10.
13
Estimate 908 + 882 by first rounding each number to the nearest 10.
14
Estimate 383 − 256 by first rounding each number to the nearest 10.
15
Estimate 810 + 363 by first rounding each number to the nearest 10.
16
Estimate 868 − 229 by first rounding each number to the nearest 10.
17
Estimate 878 + 842 by first rounding each number to the nearest 10.
18
Estimate 867 − 560 by first rounding each number to the nearest 10.
19
Estimate 869 + 115 by first rounding each number to the nearest 10.
20
Estimate 968 − 433 by first rounding each number to the nearest 10.
21
Estimate 590 + 175 by first rounding each number to the nearest 10.
22
Estimate 306 − 127 by first rounding each number to the nearest 10.
23
Estimate 549 + 364 by first rounding each number to the nearest 10.

Answer Key

1. 10802. 6003. 18004. 5805. 8206. 4107. 10008. 1909. 155010. 74011. 151012. 50013. 179014. 12015. 117016. 64017. 172018. 31019. 99020. 54021. 77022. 18023. 910

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Frequently Asked Questions

How do I download this estimating sums and differences - worksheet 9 worksheet?

Click "Download PDF" for a file, or "Print" to use your browser. You can save it as a PDF or print it directly. The answer key will be on a separate page.

How do I find worksheets at different difficulty levels?

Each subtopic has 10 worksheets: Worksheets 1-3 are Easy, 4-7 are Medium, and 8-10 are Hard. Start with Easy worksheets to build confidence, then progress to harder ones.

What skills does this addition and subtraction worksheet cover?

This worksheet focuses on estimation, rounding. It is designed for 3rd Grade students and provides structured practice through varied problem types with a worked example to guide students before they begin.

Can I use this worksheet in my classroom?

Yes. All worksheets on K12Worksheets are free for classroom use. You can print copies for your entire class. With 10 worksheets per subtopic at three difficulty levels, you have plenty of options for differentiated instruction and individualized practice.

How many problems are on this worksheet?

This worksheet contains 23 problems. It typically takes 10-15 minutes to complete. An answer key with all solutions is included so parents and teachers can check work quickly.