Alex Bellos

Earlier today I set you the following puzzle, which has been doing the rounds in the academic community, because of its counter-intuitive result. Here it is again with the solution.

Today's first puzzle was penned by Randall Munroe, cartoonist of the webcomic xkcd and author of the bestselling book What If?

Earlier today I set the following two puzzles. Here they are again with solutions. The first is by Randall Munroe, cartoonist of the webcomic xkcd and author of the bestselling book What If?

The perils of opinion polls

Deciphering an ancient number system

Earlier today I set you a puzzle about a ‘khipu', the Incan method of recording numbers with knots on string that features in Paddington in Peru. Here it is again with the answer.

Hungary acquired a reputation for brilliance in maths and physics in the middle of last century, thanks to scientists like John von Neumann, Edward Teller and Eugene Wigner.

Earlier today I set you three problems from a maths competition for Martian schoolchildren. By Martian, I mean Hungarian.

Literary logic

Earlier today I set you the following puzzle, which I read in the new Sally Rooney novel, Intermezzo. Here it is again with the solution.