To determine if 40 is a prime number or a composite number, we simply look at the factors for 40.
If the factors of 40 are only 40 and 1, then we know that 40 is a prime number. Otherwise, 40 is a composite number.
To explain better, if 40 is only divisible by 1 and 40, then it is a prime number, and if 40 is divisible by more than 40 and 1, then it is a composite number.
The factors of 40 are as follows:
1, 2, 4, 5, 8, 10, 20, 40
Therefore, since 40 is divisible by more than one and itself, the answer to the
question "Is 40 prime or composite?" is highlighted in blue below.
composite
Is 41 prime or composite?
OK. Now you know that 40 is a composite number. Use our logic above and see if
you can figure out if the next number on our list is prime or composite before you check your answer.

