Leonhard Euler

I have recently made a discovery which appears to me to be of the greatest importance.

For any polyhedron, the number of vertices minus the number of edges plus the number of faces equals 2.

The problem of the seven bridges of Königsberg is well known to be insoluble.

I have come to the conclusion that it is impossible to traverse all seven bridges exactly once.

The art of reasoning in mathematics is nothing but a part of the art of thinking in general.

All the procedures of analysis are based on the consideration of infinite processes.

The infinite is a profound and perplexing concept, yet it is indispensable in mathematics.

The theory of numbers is the queen of mathematics.

I have had my results for a long time, but I do not yet know how I am to arrive at them.

The most beautiful theorems are those which are simple in hypothesis and broad in conclusion.

The reading of all good books is like a conversation with the finest minds of past centuries.

Truth is much too simple to be found by such complex means.

The more I study, the more insatiable do I feel my genius for it to be.

A mathematician is a blind man in a dark room looking for a black cat which isn't there.

The divine law has made us so that we must be students as long as we live.

I have had to overcome tremendous difficulties; I have had to sacrifice rest, health, and fortune to my passion for mathematics.

The greatest part of my work has been done in the midst of my family, often with children on my knees.

To this day, the theory of numbers lacks the great advantages which derive from a well-developed notation.