Calendars were one of the earliest calculating devices developed by civilizations. Find out about the Mayan calendar in this article.

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.

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

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

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

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

The pages of my calendar have got mixed up. Can you sort them out?

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?

Can you fit the tangram pieces into the outline of Little Ming?

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!

Bernard Bagnall recommends some primary school problems which use numbers from the environment around us, from clocks to house numbers.

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 your own double-sided magic square. But can you complete both sides once you've made the pieces?

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

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?

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.