# Round Numbers to the Nearest Hundred to Solve Problems

In this worksheet, students will learn how to round numbers to the nearest hundred in order to estimate the answer to a calculation.

Key stage:  KS 2

Curriculum topic:   Number: Addition and Subtraction

Curriculum subtopic:   Use Rounding for Answers/Accuracy

Popular topics:   Rounding worksheets, Estimation worksheets

Difficulty level:

#### Worksheet Overview

In this activity, we will be looking at how to round numbers to the nearest 100 in order to estimate the answer to a multiplication.

Rules for rounding to the nearest 100

If the tens digit is less than 50, the number is rounded down.

If the tens digit is 50 or more, the number is rounded up.

Estimate the answer by rounding the numbers to the nearest 100 before adding.

We can ignore the 'ones' digit when rounding a 3 digit number to the nearest 100.

744 would be rounded down to 700.

751 would be rounded up to 800.

8,264 would be rounded up to 8,300

Example

242 x 164 = ?

Round each number first

242  200

164 200

Now calculate: 200 x 200 = ?

2 x 2 x 100 x 100 = 4 x 10,000 = 40,000

Top tip!

When multiplying large numbers with zeros, remove the zeros first, multiply the remaining digits and then add the zeros back!

200 x 200 Remove the four zeros: 2 x 2 = 4

Add the four zeros back on: 40,000

Easy, isn't it?!

Let's get started then!

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