A funny story told by my professor in the class today:
3 men are travelling in a hot air balloon. After some while, they are lost and didn't know where are them. They try to ask for help by shouting around: "Anyone can tell us where are we now?". They keep shouting and shouting, but no one reply. After waiting for quite a long time, they finally hear someone replying them: "You are on the hot air balloon!" The men on the hot air balloon are disappoint with the answer, and one of the men tell the other two: "The guy that answering us must be a pure mathematician." The other 2 men are wondering why and ask for explanations, he explains:
(1)The guy took a long time to answer;
(2)The answer is precise;
(3)The answer is useless.
that's all.. thank u for reading.