How_To_Be_Good_At_Math

NUMBERS • CUBE NUMBERS 39

Cube number sequence

Each cube number can be shown by an

actual cube, made from cubes of one unit.

How to cube a number

Cube numbers

A cube number is the result of multiplying a number by itself, and then by itself again.

So, now we know that the cube of 2 is 8.

When we cube numbers, we use a special

symbol – a small “3” after the number, like this: 2^3.

Let’s find the cube of 2. First, we multiply

2 × 2 to get 4. Then we multiply the answer,

4, by 2 again to make 8.

3 × 3 × 3 = 27 4 × 4 × 4 = 64

1 × 1 × 1 = 1 2 × 2 × 2 = 8

The square
numbers are
in dark purple

All the

cube’s sides

are one

unit long

because

2 × 2 × 2 = 8

Let’s start with 1:

13 = 1.

We can show the

cube number as a

single cube,

like this.

Now let’s do the

same with 2:

23 = 8. We can show

8 as a cube, too, with

sides that are two

single-unit cubes long.

2 × 2 × 2 =?

2 × 2 = 4

4 × 2 = 8

Next we

cube 3:

33 = 27.

This cube’s

sides are three

single-unit

cubes long.

Next, we

calculate

that 4^3 = 64. The

new cube has

sides that are

four single-cube

units long.

1

2

3

4 1

2

3

4

1

2

1

2

3 1

2

3

1

2

3

1

1

2

2 1

2

23 = 8

3

4

The cube is

made up of eight

small cubes

The cube is made up

of 27 small cubes

1

1

1

038_039_Square_roots_cube.indd 39 29/02/2016 14:09