Advent Calendar 2011 - a mathematical activity for each day during the run-up to Christmas.

Rather than using the numbers 1-9, this sudoku uses the nine different letters used to make the words "Advent Calendar".

Advent Calendar 2012 - a mathematical activity for each day during the run-up to Christmas.

Our 2008 Advent Calendar has a 'Making Maths' activity for every day in the run-up to Christmas.

All the activities in the 2013 advent calendar are based on the theme of planet earth.

Advent Calendar 2010 - a mathematical game for every day during the run-up to Christmas.

Advent Calendar 2010 - a mathematical game for every day during the run-up to Christmas.

Enjoy a video each day in the run up to Christmas with our Secondary Advent Calendar!

All the activities in this year's primary Advent Calendar have a food or drink theme. Yum yum!

NRICH December 2007 advent calendar - a new Sudoku for each day in the run-up to Christmas.

NRICH December 2006 advent calendar - a new tangram for each day in the run-up to Christmas.

A collection of our favourite pictorial problems, one for each day of Advent.

Twenty four tasks to count down to Christmas.

The 2012 primary advent calendar features twenty-four of our posters, one for each day in the run-up to Christmas.

A mathematical challenge for each day during the run-up to Christmas.

Explore a task from our Wild site on each day in the run up to Christmas

Twenty-four tasks for the run-up to Christmas.

Twenty four games for the run-up to Christmas.

Twenty-four tasks for the run-up to Christmas.

This advent calendar contains twenty-four tasks for the run-up to Christmas, each one encouraging mathematical creativity.

Twenty-four tasks for the run-up to Christmas, each one encouraging you to develop mathematical 'habits of mind'.

Make some celtic knot patterns using tiling techniques

Can you recreate this Indian screen pattern? Can you make up similar patterns of your own?

Make an equilateral triangle by folding paper and use it to make patterns of your own.

Paint a stripe on a cardboard roll. Can you predict what will happen when it is rolled across a sheet of paper?

It might seem impossible but it is possible. How can you cut a playing card to make a hole big enough to walk through?

It's hard to make a snowflake with six perfect lines of symmetry, but it's fun to try!

Have you noticed that triangles are used in manmade structures? Perhaps there is a good reason for this? 'Test a Triangle' and see how rigid triangles are.

Make a cube with three strips of paper. Colour three faces or use the numbers 1 to 6 to make a die.

Have a go at drawing these stars which use six points drawn around a circle. Perhaps you can create your own designs?

Make a mobius band and investigate its properties.

You could use just coloured pencils and paper to create this design, but it will be more eye-catching if you can get hold of hammer, nails and string.

Galileo, a famous inventor who lived about 400 years ago, came up with an idea similar to this for making a time measuring instrument. Can you turn your pendulum into an accurate minute timer?

Follow these instructions to make a five-pointed snowflake from a square of paper.

Using these kite and dart templates, you could try to recreate part of Penrose's famous tessellation or design one yourself.

Surprise your friends with this magic square trick.

Follow these instructions to make a three-piece and/or seven-piece tangram.

Make a clinometer and use it to help you estimate the heights of tall objects.

Here is a version of the game 'Happy Families' for you to make and play.

This article for teachers sets out some ideas for introducing children to some of the concepts at the root of mechanics.

Nowadays the calculator is very familiar to many of us. What did people do to save time working out more difficult problems before the calculator existed?

Noticing the regular movement of the Sun and the stars has led to a desire to measure time. This article for teachers and learners looks at the history of man's need to measure things.

The third of three articles on the History of Trigonometry.

Find out about the five-term project (January 2014 to July 2015) which NRICH is leading in conjunction with Haringey Council, funded by London Schools Excellence Fund.