# Estimating Numbers

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Examples, solutions, and videos to teach Grade 3 students how to round whole numbers to estimate addition and subtraction problems.

How to estimate the sum by rounding off?

1. Find the place value we want to round.
2. Round both addends to that place value.
3. Find the sum of the rounded numbers as our estimate.

The following diagram shows an example of how to find the sum using rounding off. Scroll down the page for more examples and solutions.

How to estimate a sum or difference using rounding off Examples of how you can round off numbers to the nearest 10 and add them to get a sum which is closer to the actual sum. Examples of how you can round off numbers to the nearest 10 and subtract them to get a difference which is closer to the actual difference. Adding and subtracting this way is called making estimates.

Estimate Sums
How to estimate sums by using compatible numbers, or place values, to round to the nearest ten or hundred. We compare the difference of estimating with compatible numbers to estimating with rounding to a place value. We then use data from a table to estimate sums.

Estimating Addition and Subtraction Problems Involving Whole Numbers
This video explains how to round whole numbers to estimate addition and subtraction problems.

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.