 # Estimate Sums and Differences using Benchmark Numbers

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Lesson Plans and Worksheets for Grade 4
Lesson Plans and Worksheets for all Grades

Examples, solutions, and videos to help Grade 4 students learn how to estimate sums and differences using benchmark numbers.

Topic F: Addition and Subtraction of Fractions by Decomposition

Common Core Standards: 4.NF.3c, 4.NF.3d, 4.MD.4, 4.MD.2

### NYS Common Core Grade 4 Module 5, Lesson 29

Lesson 29 Concept Development

Problem 1: Estimate the sum or difference of two mixed numbers by rounding each fraction.

Problem 2: Round two mixed numbers to the nearest half or whole, and then find the sum.

Problem 3: Estimate the difference of two fractions greater than 1.

Problem 4: Use benchmark numbers or mental math to estimate the sum and difference of two mixed numbers.
Lesson 29 Problem Set

1. Estimate each sum or difference to the nearest whole or half by rounding. Explain your estimate using words or a number line.

2. Estimate each sum or difference to the nearest whole or half by rounding. Explain your estimate using words or a number line.(Improper fractions)

3. Montoya’s estimate for 8 5/8 - 2 1/6 was 7. Julio’s estimate was 6 1/2. Whose estimate do you think is closer to the actual difference? Explain.

4. Use benchmark numbers or mental math to estimate the sum or difference.

Lesson 29 Homework

1. Estimate each sum or difference to the nearest whole or half by rounding. Explain your estimate using words or a number line.

2. Estimate each sum or difference to the nearest whole or half by rounding. Explain your estimate using words or a number line.

3. Gina’s estimate for 7 5/8 - 2 1/2 was . Dominick’s estimate was 5 1/2. Whose estimate do you think is closer to the actual difference? Explain.

4. Use benchmark numbers or mental math to estimate the sum or difference.

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