Which number between 20 and 29 has 2 and 3 in its prime factorization?

Answer 1

If it has 2 and 3 in its factorization then it will be a multiple of 6.

24 is the only number between 20 and 29 that is a multiple of 6.

The long way would be to:
List the multiples of 2:
22, 24, 26, 28
List the multiples of 3:
21, 24, 27

The one that is both is 24.

Answer 2

Prime factors:
2 * 2 * 2 * 3

Prime factors in exponent form:
23 * 3

All factors:
1, 2, 3, 4, 6, 8, 12, 24

Answer 3

24