EDEXCEL GCSE FOUNDATION MATHS - What are Cube Numbers and Cube Roots

Edexcel GCSE Foundation Maths: Cube Numbers and Cube Roots

What are Cube Numbers?

A cube number is the result of multiplying a number by itself three times.

Example:

• 2 x 2 x 2 = 8. So 8 is a cube number (2 cubed).

We can write this using the notation: 2³ = 8

Here are some examples of cube numbers:

• 1³ = 1 x 1 x 1 = 1
• 2³ = 2 x 2 x 2 = 8
• 3³ = 3 x 3 x 3 = 27
• 4³ = 4 x 4 x 4 = 64
• 5³ = 5 x 5 x 5 = 125

What are Cube Roots?

The cube root of a number is the number that, when multiplied by itself three times, equals the original number.

Example:

• The cube root of 8 is 2, because 2 x 2 x 2 = 8.

We can write this using the notation: ?8 = 2

Here are some examples of cube roots:

• ?1 = 1
• ?8 = 2
• ?27 = 3
• ?64 = 4
• ?125 = 5

Finding Cube Roots:

You can find cube roots using a calculator:

1. Look for a button on your calculator that looks like this: ?
2. Enter the number you want to find the cube root of.
3. Press the cube root button.

Example:

To find the cube root of 27:

1. Enter 27.
2. Press ?.
3. The calculator will display 3.

Finding Cube Roots Without a Calculator:

For smaller numbers, you can find the cube root by remembering the cube numbers. If you don't remember, you can use trial and error by multiplying numbers by themselves three times until you reach the desired number.