are 18 and 105 prime numbers

Answer 1

Yes, 18 is not a prime number because it has divisors other than 1 and itself (divisible by 1, 2, 3, 6, 9, and 18).

On the other hand, 105 is not a prime number because it also has divisors other than 1 and itself (divisible by 1, 3, 5, 7, 15, 21, 35, and 105).

Answer 2

any even number is divisible by 2 so 18 is NOT prime.
any number ending in 5 is divisible by 5, so 105 is NOT prime

Answer 3

Yes, that is correct. Thank you for pointing out the divisibility rule by 2 and 5 for determining if a number is prime. Both 18 and 105 are composite numbers as they have divisors other than 1 and themselves.