Question

If no digit may be used more than once, how many 2-digit numbers can be formed using only the digits 5, 6, 3, and 2?

Answer 1

use 4P2

Answer 2

= 4!/(4-2)!
= 4!/2!
= ...

Answer 3

Thanks, I feel a little stupid for not seeing the answer to that one in the first place.

Answer 4

no problem...
4! means 4 * 3 * 2 * 1 = 24
2! = 2 * 1 = 2
so, 4!/2! = 24/2 = 12