Math-Jokes :D

A pure and an applied mathematician are asked to calculate 2 * 2.

The applied mathematician's solution: We have

2 * 2 = 2 *1/(1-1/2).
The second factor on the right hand side has a geometric series expansion
 1/(1-1/2) = 1 + 1/2 +1/4 + 1/8 + ....