Leonhard Euler

Leonhard Euler was a Swiss mathematician who lived in the 1700s. He is one of the greatest mathematicians who ever lived. He wrote more math papers than any other person in history and made discoveries in almost every area of math.

A Prolific Writer

Euler wrote about 900 math papers and books. That is more than anyone else in history. He worked on algebra, geometry, calculus, and much more.

He introduced many of the symbols we still use today, like the letter e for a special number, the letter i for imaginary numbers, and the Greek letter sigma for sums.

Solving Famous Problems

Euler solved many famous problems. One was the Seven Bridges of Konigsberg puzzle. The city had seven bridges, and people wondered if you could cross all seven without going over any bridge twice. Euler proved it was impossible.

This solution started a whole new branch of math called graph theory. Euler kept working even after he went blind later in life. He did incredible math calculations in his head.

Fun Facts

• Euler had 13 children and often did math while holding a baby.
• The number e, about 2.718, is sometimes called Euler's number.
• Euler went blind in his later years but actually produced more math after losing his sight.

Did You Know?

Euler discovered a beautiful formula that connects five of the most important numbers in math: e to the power of i times pi, plus 1, equals 0. Mathematicians call it the most beautiful equation ever!