## What is a Composite Number

Composite numbers are numbers divisible by one or more numbers other than 1 and itself.

In other words, we can say that numbers having more than two factors are composite numbers.

**For Example** – 4, 6, 8, 9, 10, 12, 14, 15, 16, 18 are Composite numbers

### Which of the following numbers are Composite Numbers ?

**Example 1**

8, 2, 7

**Solution**

Factors of 8 are 2 x 2 x 2 x 1

Factors of 2 are 2 x 1

Factors of 7 are 7 x 1

Here, Factors of 8 are 2 x 2 x 2 x 1

8 is divisible by 1, 2, 4, 8

Therefore, 8 is a composite number.

**Example 2**

12, 11, 5

**Solution**

Factors of 12 are 2 x 2 x 3 x 1

Factors of 11 are 11 x 1

Factors of 5 are 5 x 1

Here, Factors of 12 are 2 x 2 x 3 x 1

12 is divisible by 1, 2, 4, 6, 12

Therefore, 12 is a composite number.

**Example 3**

17, 7, 14

**Solution**

Factors of 14 are 2 x 7 x 1

Factors of 7 are 7 x 1

Factors of 17 are 17 x 1

Here, Factors of 14 are 2 x 7 x 1

14 is divisible by 2 , 7 , 14 , 1

Therefore, 14 is composite number.

**Example 4**

28, 11, 13

**Solution**

Factors of 28 are 2 x 7 x 2 x 1

Factors of 11 are 11 x 1

Factors of 13 are 13 x 1

Here, Factors of 28 are 2 x 7 x 2 x 1

28 is divisible by 2 , 7 , 14 , 28 , 1

Therefore, 28 is composite number.

**Example 5**

5, 21, 13

**Solution**

Factors of 21 are 3 x 7 x 1

Factors of 5 are 5 x 1

Factors of 13 are 13 x 1

Here, Factors of 21 are 3 x 7

21 is divisible by 3 , 7 , 21 , 1

Therefore, 21 is composite number.