I have forgotten the number of the combination of the lock on my briefcase. I did have a method for remembering it...
6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?
How many zeros does 50! have at the end?
Find the highest power of 11 that will divide 1000! exactly.
[Factorial 1000, written 1000!, is the product of the first 1000 whole numbers 1 x 2 x 3 x ... x 1000]