Content about “
Euler

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Euler's formula

There are a million things in maths named after Leonard Euler. Here's a beautiful formula involving complex numbers.
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Perfectly even

After 2000 years of searching we only know of 51 perfect numbers and they're all even. What else do and don't we know about these rare and precious jewels of maths?

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Tricky teacups

One of our favourite problems from our sister site NRICH opens a door to the world of combinatorics and symmetry.
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The 36 officers problem

Euler may not have cracked this problem completely, but it led to a lot of important work, including on what we today know as sudoku.
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The knight's tour

Can you move a knight on a chessboard so that it visits every square exactly once? Euler was one of the first to analyse this problem systematically, but some questions about it are still open today.
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Bridges of Königsberg

The bridges of Königsberg

Can you find a path through on this city map that crosses every bridge exactly once? Euler's answer to this problem started off the filed of graph theory.