Mathematics consists in proving the most obvious thing in the least obvious way.

There exist a lot of questions that the fools can ask, and the intelligent cannot answer.

The best of ideas is hurt by uncritical acceptance and thrives on critical examination.

There are many questions which fools can ask that wise men cannot answer.

If you cannot solve the proposed problem try to solve first some related problem.

The future mathematician ... should solve problems, choose the problems which are in his line, meditate upon their solution, and invent new problems. By this means, and by all other means, he should endeavor to make his first important discovery: he should discover his likes and dislikes, his taste, his own line.

The first rule of discovery is to have brains and good luck. The second rule of discovery is to sit tight and wait till you get a bright idea.