Problems

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

Can you prove that there are arbitrarily many primes in arbitrarily big intervals?

Can you align all of the coins on the right edge of the board?

Three mathematicians discuss a beautiful flower garden and the coloured flowers within.

Two realtors discuss who's netting the award for highest average commission, but it isn't clear who the winner is...

How can you swap the coloured pegs if they can only march forward?

Please help me identify these 100 light bulbs by turning ON and OFF their switches.

25 horses racing, and you have to find out the fastest ones!

Can you find the fake ball by weighing it?

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

How can two doctors operate two patients with only two pairs of latex gloves?!

Figure out the number I'm thinking of with a single question!

Can you solve this simple-looking arithmetic challenge?

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

Can you solve this little minesweeper puzzle?

It's night time and 4 friends need to cross a fragile bridge, but they only have one torch. What's the order in which they should cross?

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

You have two magical ropes that you can set on fire and you need to count 45 minutes. How do you do it?

Two doors, one gives you eternal happiness and the other eternal sadness. How can you pick the correct one?