Lesson: Estimating Decimals Differences Mathematics • 5th Grade

In this lesson, we will learn how to estimate the difference between two decimals by rounding to the nearest whole number or using compatible numbers.

Sample Question Videos

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Lesson Worksheet

Q1:

Consider this subtraction problem.

Estimate the difference by rounding each number to the nearest whole number.

Calculate the difference.

Check that your answer is reasonable using your estimate.

Q2:

Look at how Elizabeth estimates the sum of decimal numbers by rounding each number to the nearest whole number.

She found that the sum of 3.6 and 4.27 is about 8.

Estimate the sum by rounding each number to the nearest whole number.

Estimate the difference by rounding each number to the nearest whole number.

Q3:

Anthony knows how to add and subtract 0, 0.25, 0.5, 0.75, and 1. Look at how he uses these numbers to help him estimate sums of decimal numbers.

By rounding to the nearest multiple of 0.25, he finds that is about 1.75.

Estimate the sum by rounding each number to the nearest multiple of 0.25.

Estimate the difference by rounding each number to the nearest multiple of 0.25.