Identify cube numbers
for 7th grade

Identify cube numbers

What are cube numbers?

A cube number is a number that is produced by multiplying an integer by itself twice. Examples of cube numbers include 8, 27, 64, 125, etc. The smallest cube number is 0 since 0 x 0 x 0 = 0 and zero is an integer. The number 1 is also a cube number since 1 x 1 x 1 = 1.

4 x 4 x 4 = 4³ = 64

How to identify cube numbers

The easiest way to know if an integer is a cube number is to use the cube root function on your calculator... If the answer is an integer, then the input is a cube number. Cube numbers can be positive or negative since multiplying three negative integers together always gives a negative answer. So on a number line the cube numbers extend to the left and right of zero with identical values apart from the sign:

...   -125   -64   -27   -8   -1   0   1   8   27   64   125   ...

The cube numbers to 225 (15³)

• 0 = 0 x 0 x 0 = 0³
• 1 = 1 x 1 x 1 = 1³
• 8 = 2 x 2 x 2 = 2³
• 27 = 3 x 3 x 3 = 3³
• 64 = 4 x 4 x 4 = 4³
• 125 = 5 x 5 x 5 = 5³
• 216 = 6 x 6 x 6 = 6³
• 343 = 7 x 7 x 7 = 7³
• 512 = 8 x 8 x 8 = 8³
• 729 = 9 x 9 x 9 = 9³
• 1000 = 10 x 10 x 10 = 10³
• 1331 = 11 x 11 x 11 = 11³
• 1728 = 12 x 12 x 12 = 12³
• 2197 = 13 x 13 x 13 = 13³
• 2744 = 14 x 14 x 14 = 14³
• 3375 = 15 x 15 x 15 = 15³

Types of question in this topic

This topic asks 4 different types of question.

1. Select the (only) cube number from a grid of numbers
2. Select the largest cube number from a grid of numbers
3. Count how many cube numbers there are in a grid of numbers
4. What is the cube root of the given cube number?