# Describing arrays

## Learning focus

Learn how to use an array to see the commutativity of multiplication facts (for example 3 x 5 is the same as 5 x 3).

This lesson includes:

• two videos
• three activities

# Learn

### Repeated addition and multiplication: Describing arrays

Watch this animation from 1st Level Maths and Numeracy. Fin and Snoot count Meebs by putting them into equal rows and columns.

## What is an array?

An array is a way of representing multiplication facts in a diagram or picture. It is always rectangular and made up of rows and columns.

An array is helpful for calculating multiplication statements, for example, 2 x 4 which can be shown using this array:

• There are 2 rows of apples and 4 apples in each row.

• There are 4 columns of apples and 2 apples in each column.

This array shows the multiplication statements 2 x 4 and 4 x 2.

The array has 8 apples in total. This tells us that 2 x 4 and 4 x 2 are both equal to 8.

2 x 4 = 8 and 4 x 2 = 8

## Example 1:

Here is an array to show a multiplication fact:

• There are 3 rows of sweets and 5 sweets in each row.

• There are 5 columns of sweets and 3 sweets in each column.

This array shows the multiplication statements 3 x 5 and 5 x 3.

The array has 15 apples in total. This tells us that 3 x 5 and 5 x 3 are both equal to 15.

3 x 5 = 15 and 5 x 3 = 15

## Top tip

Remember multiplication is commutative.

4 x 3 is the same amount as 3 x 4.

4 lots of 3 is the same amount as 3 lots of 4.

## Example 2:

Here is an array to show 6 x 2

• Can you see 6 lots of 2?

• Can you see 2 lots of 6?

• How many footballs are there in the array?

This array shows that 6 x 2 = 2 x 6.

Now let's recap with this video from KS1 Maths. Can you think how you might show 3 x 7 using an array?

# Practise

## Activity 1

1. Can you draw an array to show 3 x 4?

2. Which other multiplication fact does it show?

### Remember

An array is a rectangular diagram to show a multiplication fact. It always has rows and columns and shows that multiplication is commutative.

## Activity 2

Make an array activity

Try this interactive activity to see if you can answer the question by making your own array.

## Activity 3

Worksheet: Using arrays

This worksheet from Classroom Secrets Kids contains three tasks about using arrays. Have a go and see if you can get them all correct.

Finished? Check here for the answer sheet

# Play

Test your skills on this topic even further by playing Karate Cats Maths - see if you can collect a new costume for your cat!

# There's more to learn

Have a look at these other resources.