Few days ago, Vincent posted this maths question to me. He says it was a question from 2002 maths olympiad competition.

He, being very smart, managed to solve it by himself!

Me, being quite stupid, went the wrong way, trying very hard to solve it, and did not manage to solve it, after half an hour. Luckily, with the help of Vincent, I solved it! (:

Below is the maths question. Anyone interested, can try solving. It took less than half a page to solve, if you do it in the right way! (:

W/O using a calculator evaluate (1 + tan 21)(1 + tan 22)(1 + tan 23)(1 + tan 24).

A hint: make use of tan 45 = 1 (: good luck!
The answer....... is 4
hmmm nice number. (:

Maths is so... wonderful, beautiful and incredible! (: