Question

One of the numbers in the list 13,17,21,23 and 29 is different from the rest. Which one, and why?

Answer 1

23 is different in the list. Because difference between all the numbers is 4. But difference between 21 and 23 is 2, so instead of 23,the number should be 25

Answer 2

Answer:

21

Step-by-step explanation:

because all the numbers only have have two factors, 1 and itself, except 21.