Question

why we check for the conditions with numbers 2 3 5 7 while checking prime numbers

Answer 1

For a number to be prime,it must only be divisible by 1 and itself.
Here 2,3,5,7 are divisible by 1 and itself so they are prime

Answer 2

For a number to be prime, it must only be divisible by 1 and itself.
Here, 2,3 5,7 are doviaible by 1 and itself so they are prime.