Correct. For those who don't know what factorial is, it's basically multiplying all of the numbers going down one from the number you're at, so for example, 5 factorial would be 5 x 4 x 3 x 2 x 1 (we leave out the x 1 since it's a bit pointless).

Anyways, since you cannot have repeating numbers for this problem, the first digit has 5 possibilities, the second digit has 4 possibilities (because the first digit used one of those 5 possibilities), the third digit and 3 possibilities, and so forth.

The answer would be 120.

Edited by HybridCore - 1/26/13 at 2:08pm