Divide fractions by integers

Learning focus

In this lesson you will learn how to divide fractions by a whole number.

This includes:

• one learning summary
• one quiz

Learn

We're going to learn about dividing fractions by a whole number.

We will use images to visualise the problems, feel free to draw your own if it helps your understanding.

Divide fractions by integers

To divide fractions by a whole number, we divide the numerator by the whole number and the denominator stays the same.

Example 1

This jug of juice is $$\frac{4}{5}$$ full and we need to share it out between two cups.

How much will be in each cup?

The calculation is $$\frac{4}{5}$$ ÷ 2.

We know that 4 ÷ 2 = 2 so we can use that knowledge here.

You can visualise what $$\frac{4}{5}$$ looks like with these bar models and how that is split between two.

To work this out without using images we divide the numerator by the whole number and keep the denominator the same.

$$\frac{4}{5}$$ ÷ 2 = $$\frac{2}{5}$$ .

Example 2

There is $$\frac{9}{10}$$ of a pizza left and we need to share it equally between 3 people.

As a fraction, how much pizza will each person receive?

As a calculation this is $$\frac{9}{10}$$ ÷ 3

Let's take a look at this problem visually.

We started with $$\frac{9}{10}$$ and then shared out the $$\frac{9}{10}$$ to 3 people.

9 ÷ 3 = 3 so each person gets $$\frac{3}{10}$$

Another way to work this out without using a diagram is to divide the numerator by the whole number and keep the denominator the same.

$$\frac{9}{10}$$ ÷ 3 = $$\frac{3}{10}$$ .

Practise

Activity 1

Take this quiz and see if you can divide fractions by a whole number