Question

Of the following numbers which one is prime 14 13 21 33

Answer 1

A prime number is a number which is only divisible by itself and 1.
No even numbers can be primes because they are all divisible by 2.
Therefore, 14 is not a prime number.
21 ÷ 3 = 7
33 ÷ 3 = 11
That leaves 13.

13 is a prime number.

Answer 2

13 is the prime number

Explanation:

You must take into account that a prime number is one that is just divisible by 1 and itself. So, let's analyse each number.

Number 14

If you divide 14 by 1 you obtain 14.

If you divide 14 by 14 you obtain 1.

If you divide 14 by 2 you obtain 7.

If you divide 14 by 7 you obtain 2.

14 is not prime because is divisible by 1, 2, 7, and 14

Number 13

If you divide 13 by 1 you obtain 13.

If you divide 13 by 13 you obtain 1.

13 is a prime number because it can't be divided by other number, just 1 and itself

Number 21

If you divide 21 by 1 you obtain 21.

If you divide 21 by 21 you obtain 1.

If you divide 21 by 3 you obtain 7.

If you divide 21 by 7 you obtain 3.

21 is not prime because is divisible by 1, 3, 7, and 21

Number 33

If you divide 33 by 1 you obtain 33.

If you divide 33 by 33 you obtain 1.

If you divide 33 by 3 you obtain 11.

If you divide 33 by 11 you obtain 3.

33 is not prime because is divisible by 1, 3, 11, and 33

Thus, 13 is the prime number