Interview Question for Systems Engineer at Google:

There are 24 trailing zeros. 100*99*98*97*...*2*1. A simple brain-teaser meant to recognize patters of multiplying successive multiples of ten and five.

5!=120. So there is 1 trailing zero.

5!=120. So there is 1 trailing zero.

This sounds like one geared not so much towards getting the right answer, but getting to it the right way. If you think a bit and say "one", the interviewer will know you did it the brute-force way, doing the math. You'd get at the answer faster, and probably impress them more, if you think instead how many times a ten will be produced in doing that math, rather than what the actual result of the math will be.