Question

Write down separately the prime numbers and composite numbers less than $20$?

Answer 1

Finding the prime numbers and composite numbers less than $20$:

Prime Numbers:The numbers which have only two factors $1$ and the number itself are called Prime Numbers.

Composite Number:A number having more than two factors is known as Composite Numbers.

$1$ is neither prime nor composite number.

Therefore, the prime numbers less than $20$ are $2,3,5,7,11,13,17,19$ and

The composite numbers less than $20$ are $4,6,8,9,10,12,14,15,16,18$.