# Find the Answer by Doing the Inverse Operation

In this worksheet, students will use the inverse operation to check answers to addition and subtraction questions.

Key stage:  KS 2

Curriculum topic:   Number: Addition and Subtraction

Curriculum subtopic:   Use Correct Methods to Problem Solve

Difficulty level:

#### Worksheet Overview

This is called the inverse operation. Clever!

In this activity, we are going to practise checking our answers using the inverse operation.

Example

650 + 125 =

We can probably work out the answer mentally.

650 + 125 = 775

It is always worth checking our answers.  This is quite an easy example, but sometimes we'll have much more difficult questions to answer, so it's worth having a good method for checking!

Let's check

The opposite (inverse) of addition is subtraction.

So we work out 775 - 125 = 650

Let's have a look at another one using subtraction

630 - 220 = 410

Now, let's use the inverse operation to check we have the correct answer.

220 + 410 = 630

Now it's your turn to have a go at using the inverse operation to check some answers - good luck!

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