A sequence where order distinguishes one sequence of things from another order of the same things is called a permutation. Suppose we have things a, b, and c. Drawing without replacement 3 times produces the permutations {abc, acb, bac, bca, cab, and cba}. We see 3 things have 6 permutations or orders. Let's generalize. For a sequence of n things drawn from N things without replacement, there are N ways the 1st draw occurs. For each of the N outcomes of 1st draw, there are N-1 ways the 2nd draw can occur. So, for 2 draws, there are N x (N - 1) possible permutations. Continuing, there are N x (N-1) x (N-2) permutations for 3 draws. In general, it's N x (N - 1) x (N - 2) x . . . x (N - n +1) = N! / (N - n)! , or using Excel functions, =PERMUT( N, n) ! is read factorial Example: 6! = 6 x 5 x 4 x 3 x 2 x 1 For additional reading How many permutations can be formed by sampling 5 things from 8 different things without replacement?