How many zeros are there at the end of 125!?

Explanation

1. 01

   Count the factors of 5 in $1 \times 2$ × … × 125.

2. 02

   $125 \div 5 = 25$, $125 \div 25 = 5$, $125 \div 125 = 1$.

3. 03

   Trailing zeros = $25 + 5 + 1 = 31$.