Blog posts with problems to get your brain going! You get a new problem every fortnight and the solutions are published later.

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The next problem is scheduled for Sunday, 13th of December.

You may notice some problems are missing... I'm still migrating articles from my old blog.


Some people are standing quiet in a line, each person with a hat that has one of two colours. How many people can guess their colour correctly?

In this problem you have to devise a strategy to beat the computer in a "guess the polynomial" game.

This simple problem is an example of a very interesting phenomenon: if you have a large enough "universe" to consider, even randomly picked parts exhibit structured properties.