Question

Is 93 prime?

Answer 1

No, `93` is divisible by 3, it is therefore not prime.

Explanation:

By inspection you should be able to see that `93` is definitely not prime .... it clearly divides by 3!

`93 div 3 = 31`

There are 25 prime numbers less than 100.

Be careful of the following five numbers which are often mistakenly thought to be prime.

`1" "51" "57" "87" "91`