Hi permutations and combinations for 3 of 4 digits: 3,5,7,9 permutations = 4P3 = 4! = 24 combinations = 4C3 = 4!/3! = 4 Note: Combinations (order not important) are: (3,5,7) (3,5,9) (3,7,9) & (5,7,9)