Trailing zeros in 100!

What is the trailing number of zeros in 100!

Just compute zeros in , n * 8 * 10
we choose 8 because that is the max even num, 
that produces the max num of zeros.
----------------------
                Zeros
----------------------
(5  * 8  * 10)  = 2
(15 * 18 * 20)  = 2
(25 * 28 * 30 ) = 3
(35 * 38 * 40)  = 2
(45 * 48 * 50 ) = 3
(55 * 58 * 60 ) = 2
(65 * 68 * 70)  = 2
(75 * 78 * 80 ) = 3
(85 * 88 * 90)  = 2
(95 * 98 * 100) = 3