Find the last two digits of the following sum: 5! + 6! + 7! + 8! + 9! + 10! + ... + 100!
10! and any greater integer factorial will always end in two zeroes
So.....
5! = 120
6! = 720
7! = 5040
8! = 40320
9! = 362880
So...... the sum has the last two digits = 20 + 20 + 40 + 20 + 80 = _80
