The run-up to Christmas is a busy time, so why not make a cup of tea, put your feet up for a few minutes, and learn some maths at the same time? Each door of this year's advent calendar conceals a favourite item from our Maths in a minute series, explaining important mathematical concepts in just a few words.
Find out what's behind today's door!
Follow Plus on Twitter and Facebook, subscribe to our RSS feed or get Plus delivered straight to your inbox!
Nice idea, God bless all Plus magazine; and Maths in a minute series team.