How many 7 number combinations can be made with 8 numbers?

Answer 1

8*7*6*5*4*3*2

8P7

=40,320

1. If you are really asking for combinations, in other words, if the order of the numbers chosen doesn't matter :

If each number can be selected only once, this is the number of choices of 7 from 8 _without replacement_:

8 choose 7 = 8

If each number can be selected more than once, this is the number of choice of 7 from 8 _with replacement_:

( 8 + 7 - 1 ) choose 7 = 3432

2. If the order of the numbers chosen matters as well as the combinations :

If each number can be selected only once, then there are 8 choices for the 1st number, 7 for the next, 6 for the one after that, and so on, or 8*7*6*5*4*3*2, as in the first answer.

However, if each number can be selected more than once, then there are 8 choices for the 1st number, (still) 8 choices for the next, 8 choices for the one after that, and so on, or 8*8*8*8*8*8*8 = 2097152.