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

Nothing is more important than to see the sources of invention which are, in my opinion, more interesting than the inventions themselves.

An idea which can be used once is a trick. If it can be used more than once it becomes a method.

Analogy pervades all our thinking,

In order to solve this differential equation you look at it till a solution occurs to you.

The principle is so perfectly general that no particular application of it is possible.

It is better to solve one problem five different ways, than to solve five problems one way.

Solving problems is a practical art, like swimming, or skiing, or playing the piano: you can learn it only by imitation and practice.

Good problems and mushrooms of certain kinds have something in common; they grow in clusters.

Success in solving the problem depends on choosing the right aspect, on attacking the fortress from its accessible side.

Mathematics is being lazy. Mathematics is letting the principles do the work for you so that you do not have to do the work for yourself

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

Geometry is the science of correct reasoning on incorrect figures.

I am too good for philosophy and not good enough for physics. Mathematics is in between.

When introduced at the wrong time or place, good logic may be the worst enemy of good teaching.

If there is a problem you can't solve, then there is an easier problem you can't solve: find it.

A mathematics teacher is a midwife to ideas.

It may be more important in the mathematics class how you teach than what you teach.

Look around when you have got your first mushroom or made your first discovery: they grow in clusters.