10!
____ =
5^2
10* 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
__________________________ =
5 * 5
( 5 * 2)* 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
______________________________ =
5 * 5
4! * 6 * 7 * 8 * 9 * 2
4! ends in 4
6 * 7 * 8 * 9 * 2 ends in 8
So
10!
____ ends in 2
5^2
