Question

Determine whether 97 is prime, composite or ne ther.

Answer 1

To find whether a number is prime or not, check if it is divisible by any prime number less than its square root.

First, notice that:

$\sqrt[]{97}\approx9.84$

The prime numbers lower than 9.84, are:

$2,3,5,7$

Check for divisibility for each of those prime numbers:

97 is not divisible by 2 since its last digit, 7, is an odd number.

97 is not divisible by 3 since 9+7=16, which is not divisible by 3.

97 is not divisible by 5 since its last digit, 7, is neither 5 or 0.

97 is not divisible by 7, since 97 is between the multiples of 7 91 and 98.

Therefore, 97 is a prime number.