For a positive integer,$\displaystyle N$, we define N! (read N factorial) to

be the product of all the integers from 1 to N. Thus:

$\displaystyle N! = 1 . 2 . 3 .... . N$

It is clear that N! will end in a zero if N is larger or equal to

5. For big values of N, N! will end in many, many zeros.

How many zeros will $\displaystyle 75!$ end in?