Multiplying and dividing by 8

Learning focus

In this session you will learn to multiply and divide by 8.

This includes:

  • one learning summary
  • one quiz

Learn

Counting in 8s

Count forwards and backwards in eights using this counting stick.

If we know the answer to a multiplication number sentence or multiplication fact we can work out the answer to an unknown number sentence by adding or subtracting.

Use the counting stick to help work out what 6 × 8 is.

6 × 8 = 48

If we know 6 × 8, how could this help us to work out 7 × 8?

We just add another 8.

7 x 8 = 56

A multiplication fact is the answer to a multiplication calculation.

In 6 × 8 = 48 the multiplication fact is 48.

Example 1

How many apples are in this image?

How could you work it out without counting each apple?

Count the apples along the top row. There are 8.

Now count the apples in the left-hand column. There are 5.

There are 8 lots of 5 (or 5 lots of 8). You can write this as 8 x 5 or 5 x 8.

8 x 5 = 40

How would we work out 8 x 4?

To work out 8 x 4 we take away 8 from 40.

8 x 4 = 32

Example 2

There are 11 octopuses swimming near the shore. How many legs are there altogether?

We know that octopuses have 8 legs, so the equation we need to work out is 11 x 8.

We know from looking at the number stick that:

10 x 8 = 80

So to find 11 x 8 we add another 8.

11 x 8 = 88

So, there are 88 legs altogether.

Dividing by 8

Division facts are division number sentences related to a times table.

If we know from the previous example that 6 × 8 = 48 then a division fact related to this could be 48 ÷ 8 = 6

We can use known division facts to work out unknown division facts.

There are 56 sweets and we want to share them between 8 people.

56 ÷ 8 = 7

If 56 ÷ 8 = 7 then 56 ÷ 7 =?

Using the number fact 56 ÷ 8 = 7 we can work out that 56 ÷ 7 = 8

Practise

Activity 1

Use your knowledge of multiples of 8 to multiply and divide by 8 in this quiz.

There's more to learn

Have a look at these other resources.

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