Year 9 Interactive Maths - Second Edition

Cubes

We know that: 

In general:

Example 7

Find the cube of 6.

Solution:

Cube of a Negative Number

We know that:

From the above, we can infer that:

• The cube of a positive number is positive.

• The cube of a negative number is negative.

Example 8

Find the cube of –10.

Solution

Properties of Cubes

Consider the cube of numbers greater than 1. 

Clearly, the cubed value is much greater than the number being cubed.

In general:

Consider the cube of fractional numbers, i.e. the numbers which are between 0 and 1.

Clearly, the cubed value of a fractional number is much less than the number being cubed.

In general:

Key Terms

cube, properties of cubes