# Finding an Exponent of −1(KS3, Year 8)

## The Lesson

A number with an exponent of -1 is equal to the reciprocal of the number (1 divided by the number). Imagine we have the number 2 with an exponent of -1. This is equal to 12.

This is a law of exponents.

## How to Find an Exponent of −1

Finding an exponent of −1 is easy.

## Question

Use the law of exponents to find the power with an exponent of −1 below.

# 1

Find the number that has an exponent of −1. In our example, the number is 3.

# 2

Write 1 on the top of a fraction (called the numerator).

# 3

Write the letter from Step 1 (3) on the bottom of the fraction (called the denominator).

We have found an exponent of −1.

## Understanding Finding an Exponent of −1

Let us look at the rule for an exponent of −1:

## Lesson Slides

The slider below shows another real example of how to find an exponent of −1. Open the slider in a new tab

## What Is a Reciprocal?

A reciprocal of a number is 1 divided by the number.

## Reciprocal of a Fraction

The reciprocal of a fraction just flips the fraction upside down.

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