In this activity, we will be finding common factors, multiples and prime numbers*.*

**Common Factors**

Factors are numbers that we multiply together to make another number.

When we find the factors of two or more numbers that are the same, then they are called **common factors**.

__ Example__: 12 and 16

Factors of 12: 1, 2, 3, 4, 6 and 12

Factors of 16: 1, 2, 4, 8 and 16

The common factors of 12 and 16 are **1, 2 **and **4.**

The highest common factor of two numbers is the largest whole number which is a factor of both.

The** highest common factor of 12 and 16** is **4.**

__Multiples__

The multiples of a number are the numbers that form its times table.

A **common multiple **is a whole number that is a shared multiple of two or more sets of numbers.

__Example__

Multiples of 3 and 4:

Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30

Multiples of 4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40

The** common multiples of 3 and 4** are: **12 **and **24.**

__Prime Numbers__

A prime number is a number only divisible by itself and 1.

So, prime numbers have only** two factors.**

__Example__

What are the prime numbers between 10 and 30?

**Answer**: 11, 13, 17, 19, 23, 29

These numbers have no factors except for the number 1 and the number itself.

That's a lot to remember, but it will become easier the more we practise.

Let's get started!