You can send your solution by e-mail to plus@maths.cam.ac.uk.
For some challenging mathematical puzzles, see the NRICH puzzles from this month or last month.
Want facts and want them fast? Our Maths in a minute series explores key mathematical concepts in just a few words.
Weird and wonderful things can happen when you set a ball in motion on a billiard table — and the theory of mathematical billiards has recently seen a breakthrough.
Was vaccinating vulnerable people first a good choice? Hindsight allows us to assess this question.
A game you're almost certain to lose...
What are the challenges of communicating from the frontiers of mathematical research, and why should we be doing it?
Celebrate Pi Day with the stars of our podcast, Maths on the move!