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

If you want the problems delivered to your inbox be sure to subscribe to the Problems newsletter.

The next problem is scheduled for late June.

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

How many matches does it take to find the winner of a tennis tournament?

Can you help these kids trick or treat their entire neighbourhood in this Halloween special?

If I scramble a Rubik's cube for long enough, will it solve itself?

Three friends are given three different numbers that add up to a dozen. Can you figure out everyone's numbers?

This is an algorithmic puzzle where you just have to turn some coins.

Syncro is a beautiful game where you have to unite all the petals in a single flower. In how many moves can you do it?

A waiter at a restaurant gets a group's order completely wrong. Can you turn the table to get two or more orders right?

A bunch of ants are left inside a very, very, tight tube, and they keep colliding with each other and turning around. How long will it take them to escape?

This problem is a step up from Problem #028 - hidden key. Can you tackle this one?

There is a key hidden in one of three boxes and each box has a coin on top of it. Can you use the coins to let your friend know where the key is hiding?

I bet you have seen one of those Facebook publications where you have a grid and you have to count the number of squares the grid contains, and then you jump to the comment section and virtually no one agrees on what the correct answer should be... Let's settle this once and for all!