Cubes

Cubes

Basic GCSE(F)

Multiplying a number by itself, then multiplying by itself again is cubing a number:

4 x 4 x 4 = 43 = 64.

The small 3 after the number indicates that it is being cubed.

A negative number that is cubed will result in a negative number:

-33 = -3 x -3 x -3 = -27

A number less than 1 will result in a smaller number:

0.23 = 0.2 x 0.2 x 0.2 = 0.008

Fractions can also be cubed:

(`frac(1)(2)`)3 = `frac(1)(2)` x `frac(1)(2)` x `frac(1)(2)` = `frac(1)(8)`

Examples

1. What is 0.53?

Answer: 0.125

Work out 5 x 5 x 5 = 125: there were 3 x 1 decimal places in the original numbers, make sure that there are three decimal places in the answer = 0.125.

2. Calculate (2 + 3)3.

Answer: 125

Calculate the brackets first: 2 + 3 = 5.

53 = 5 x 5 x 5 = 125.