Vincent and Tara are making triangles with the class construction set. They have a pile of strips of different lengths. How many different triangles can they make?

Imagine that the puzzle pieces of a jigsaw are roughly a rectangular shape and all the same size. How many different puzzle pieces could there be?

At the beginning of May Tom put his tomato plant outside. On the same day he sowed a bean in another pot. When will the two be the same height?

If I use 12 green tiles to represent my lawn, how many different ways could I arrange them? How many border tiles would I need each time?

Follow the journey taken by this bird and let us know for how long and in what direction it must fly to return to its starting point.

Here you see the front and back views of a dodecahedron. Each vertex has been numbered so that the numbers around each pentagonal face add up to 65. Can you find all the missing numbers?

Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.

Investigate what happens to the equation of different lines when you translate them. Try to predict what will happen. Explain your findings.

Investigate what happens to the equations of different lines when you reflect them in one of the axes. Try to predict what will happen. Explain your findings.

Each of the main diagonals of this sudoku must contain the numbers 1 to 9 and each rectangle width the numbers 1 to 4.

Build gnomons that are related to the Fibonacci sequence and try to explain why this is possible.

These gnomons appear to have more than a passing connection with the Fibonacci sequence. This problem ask you to investigate some of these connections.

I took the graph y=4x+7 and performed four transformations. Can you find the order in which I could have carried out the transformations?

Can you work out the means of these distributions using numerical methods?

Get into the exponential distribution through an exploration of its pdf.

How is the length of time between the birth of an animal and the birth of its great great ... great grandparent distributed?

The solution to this problem depends on how you thought of a 'move'. Jessica and Elijah explain their methods well but don't agree on the answer!

Morgan, Sara, Billie and Lucy discovered some rules for predicting what will happen when you join the numbers round the circle in different step-sizes.

James and Dylan showed clear mathematical thinking to prove this result about quadrilaterals.

This article, written for teachers, looks at the different kinds of recordings encountered in Primary Mathematics lessons and the importance of not jumping to conclusions!

Written for teachers, this article discusses mathematical representations and takes, in the second part of the article, examples of reception children's own representations.

Vicki Pike was one of four NRICH Teacher Fellows who worked on embedding NRICH materials into their teaching. In this article, she writes about her experiences of working with students at Key Stage two.

We asked what was the most interesting fact that you can find out about the number 2009. See the solutions that were submitted.

This is the second article in a two part series on the history of Algebra from about 2000 BCE to about 1000 CE.

A personal investigation of Conway's Rational Tangles. What were the interesting questions that needed to be asked, and where did they lead?