How_To_Be_Good_At_Math

99

It doesn't matter

which order you

multiply numbers in

• the total will be
  the same.

CALCULATING • MULTIPLICATION

Multiplication as scaling

We can think of multiplication as adding together more than

one quantity of the same size. We call this repeated addition.

To multiply two numbers, we just have to add one number in the

calculation to itself the number of times of the other number.

Let's work out the answer to the

calculation 5 × 4 using some apples. We

want to multiply 5 by 4, so let's look at 4 rows

of 5 apples to help us find the answer.

5 × 4 =?

So, using repeated addition, we can

see that 5 × 4 = 20

Multiplication

challenge

Here are some examples

of repeated addition.

Can you write them

as a multiplication

calculation and

work out the answer?

6 + 6 + 6 + 6 =?

8 + 8 + 8 + 8 + 8 + 8 + 8 =?

9 + 9 + 9 + 9 + 9 + 9 =?

13 + 13 + 13 + 13 + 13 =?

TRY IT OUT

To work out how many apples there

are in total, we just have to add

4 lots of 5: 5 + 5 + 5 + 5 = 20

Answers on page 319

5 × 4 = 20

=

3 groups
of 4
oranges

5

5

5

5

20

098_099_Multiplication.indd 99 29/02/2016 16:39