Welcome to the factorial world :) Remember the Exclamation Point ( ! ) on the calculator, that is called factorial. For instance: 1! = 1 2! = 1 x 2 3! = 1 x 2 x 3 and so on 10! = 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 = 3628800 Crazy enough, 0! is actually equal to 1, try that on your calculator XD
