n! means n × (n − 1) × … × 3 × 2 × 1
For example, 10! = 10 × 9 × … × 3 × 2 × 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
Find the sum of the digits in the number 100!
Here is my solution in Python
import math total = 0 foo = math.factorial(100) while foo > 0: rem = foo % 10 total += rem foo = (foo - rem)/10 print total