Trailing zeroes in fibonacci number

Calculate trailing zeroes in fibonacci number

10 = 5 * 2
10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1

20...15...10...5

11%5 = 1
10/5 = 2

15/5 = 3
20/5 = 4
25/5 = 5
30/5 = 6

10/5 = 2