Find the number of trailing zeros of the number .
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Since the factors 5 and 2 are needed to make a trailing zero, we can take the floor function of how many times the powers of 5 divide 60 (since they are less common than powers of 2).
⌊ 5 6 0 ⌋ + ⌊ 5 2 6 0 ⌋ = 1 2 + 2 = 1 4
In general, the number of trailing zeroes in x! = ⌊ 5 x ⌋ + ⌊ 5 2 x ⌋ + ⌊ 5 3 x ⌋ . . . + ⌊ 5 n x ⌋ w h e r e 5 n + 1 x < 1 < 5 n x
NB: ⌊ x ⌋ is the floor function of x and is used to denote the largest integer not greater than x