# What is the composite number between 20 and 40?

Nov 14, 2016

#### Answer:

All of the following are composite:

$20 , 21 , 22 , 24 , 25 , 26 , 27 , 28 , 30 , 32 , 33 , 34 , 35 , 36 , 38 , 39 , 40$

#### Explanation:

A composite number is any number which has factors apart from $1$ and itself.

So most numbers between $20$ and $40$ are composite:

$20 = 2 \times 2 \times 5$

$21 = 3 \times 7$

$22 = 2 \times 11$

$24 = 2 \times 2 \times 2 \times 3$

$25 = 5 \times 5$

$26 = 2 \times 13$

$27 = 3 \times 3 \times 3$

$28 = 2 \times 2 \times 7$

$30 = 2 \times 3 \times 5$

$32 = 2 \times 2 \times 2 \times 2 \times 2$

$33 = 3 \times 11$

$34 = 2 \times 17$

$35 = 5 \times 7$

$36 = 2 \times 2 \times 3 \times 3$

$38 = 2 \times 19$

$39 = 3 \times 13$

$40 = 2 \times 2 \times 2 \times 5$

The only prime numbers (having no factors apart from $1$ and themselves) between $20$ and $40$ are: $23 , 29 , 31 , 37$.