If using numbers 1 through 5 how man different combinations can be made?

Answer 1

It depends on whether each number is used (a) at most once, (b) exactly once or (c) as many times as you like.

The answers are

(a) 5 + 5*4 + 5*4*3 + 5*4*3*2 + 5*4*3*2*1 = 5+20+60+120+120 = 325

(b) 5*4*3*2*1 = 120

(c) infinite