How many combinations of 9 if you had to use all 9?

Answer 1

Applying the formula n!/(n - r)! to the numbers n = 9 and r = 9, where n is the number of numbers to choose from, and r is the number of numbers chosen, 9! / (9 - 9)! is equal to 9 factorial. This is equal to 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 362880 combinations.