Doubling numbers

Part of MathsMultiplying and dividingYear 3Year 3

How do you double numbers?

Double means two lots of something. There are two ways to double numbers.

You can add the number to itself to get a double.

3 groups of apples. Five apples in a column in the first group and the same for the second group. In the third group, there are 10 apples separated into two columns of 5 apples. Below the apples, text reads: 5 + 5 = 10

You can also multiply a number by 2 to get a double.

When you double a number, it ends up twice as big.

10 apples are arranged in two rows. Below the apples, text reads: 5 × 2 = 10
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Quiz: Doubling numbers

Test out your knowledge of doubling numbers with this quiz, then read on to complete the page.

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Doubling using ten frames

You can work out how to double by using ten frames.

Here is a ten frame with 3 counters.

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  1. A two by 5 grid. Three squares are filled with counters.

    To find double 3, just add the same number of counters to the ten frame.

Here’s another example of how to use ten frames when doubling.

This time the ten frame has 6 counters.

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  1. A two by 5 grid. Six squares are filled with counters, 3 on each row.

    There is not enough room to add 6 more counters to double 6. So you need an extra ten frame.

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Doubling using addition

To find doubles using addition, all you need to do is add the number to itself.

Take a look at these calculations and explore how to double the numbers 1 to 9 using addition.

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  1. Two single blocks with the text "1 + 1 = 2" below. On the right, two blocks are stacked on top of each other.
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Doubling using multiplication

To find doubles using multiplication, all you need to do is multiply the number by 2.

Take a look at these calculations and explore how doubles of the numbers 1 to 9 are made using multiplication.

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  1. Two cubes stacked on top of each other. The equation underneath shows 1 × 2 = 2.
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Example 1

Here are 8 counters.

A 2 by 5 grid filled with eight counters, 4 on each row.

What is double 8?

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Example 2

A boy in a wheelchair is sitting on the left. Eight shells are grouped into two sets of four. Below them is the equation 4 + 4 =.

John collects 4 shells from the beach. The next day, he collects more shells and ends up with double the amount of shells.

How many shells does John have in total?

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Example 3

A girl holding a balloon is standing next to the numbers 7 × 2 =.

Omi has 7 balloons. Later, she has double the number of balloons.

How many balloons does Omi have now?

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