 This calculation is the number of ways of obtaining an ordered subset of r elements from a set of n elements. n = the set size. It is the total number of items in the sample. r = the subset size. It is the number of items chosen from the sample. Only whole positive (integer) numbers are valid. Permutations gives the number of ways a subset of r items can be chosen out of a set of n items and different arrangements of the same items are also counted. For r <= n, n >= 0, and r >= 0. The permutations formula is (P(n,r) = n! / (n  r)!)... NPR Permutations Calculator This will calculate the permutations for P(n,r) = n! / (n  r)!. View the source...  
