Year 8: Special numbers

This cheat-sheet covers some key concepts related to special numbers in mathematics.

Prime Numbers

A prime number is a whole number greater than 1 that has only two divisors: 1 and itself. Examples: 2, 3, 5, 7, 11, 13, 17...

How to check: Divide the number by all integers from 2 up to the square root of the number. If it's divisible by any, it's not prime.

Composite Numbers

A composite number is a whole number greater than 1 that has more than two divisors. It can be expressed as the product of prime numbers.

Example: 12 = 2 x 2 x 3

Square Numbers

A square number is a whole number that can be obtained by squaring an integer. They always end in 0, 1, 4, 5, 6 or 9.

Example: 9 = 3 x 3, 16 = 4 x 4

Perfect Squares

A perfect square is a number that is the result of squaring an integer. This is the same as a perfect square.

Perfect Cubes

A perfect cube is a number that is the result of cubing an integer. It is the result of multiplying an integer by itself three times.

Example: 8 = 2 x 2 x 2

Fibonacci Sequence

A sequence of numbers where each number is the sum of the two preceding ones. It starts with 0 and 1. Examples: 0, 1, 1, 2, 3, 5, 8, 13, ...