There are 16C6 combinations = 16!/(6!(16-6)!) = 16!/(6!10!) =8,008 possible combinations.Assuming the 16 numbers are the hexadecimal digits 0-F, theyare:{0, 1, 2, 3, 4, 5}, {0, 1, 2, 3, 4, 6}, {0, 1, 2, 3, 4, 7},...., {0, 1, 2, 3, 4, E}, {0, 1, 2, 3, 4, F},{0, 1, 2, 3, 5, 6}, ..., {0, 1, 2, 3, 5, F},{0, 1, 2, 3, 6, 7}, ...., {0, 1, 2, 3, 6, F}, ...., {0, B, C, D,E, F}, {1, 2, 3, 4, 5}, ...,{9, A, B, C, D, E}, {9, A, B, C, D, F}, {9, A, B, C, E, F}, {9,A, B, D, E, F},{9, A, C, D, E, F}, {9, B, C, D, E, F}, {A, B, C, D, E, F}I'll let you fill in the missing 7,990 possiblecombinations.