Here is your chance to investigate the number 28 using shapes, cubes ... in fact anything at all.

What could these drawings, found in a cave in Spain, represent?

Can you help the children in Mrs Trimmer's class make different shapes out of a loop of string?

Can you find ways of joining cubes together so that 28 faces are visible?

Investigate and explain the patterns that you see from recording just the units digits of numbers in the times tables.

In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?

There are ten children in Becky's group. Can you find a set of numbers for each of them? Are there any other sets?

Mathematicians are always looking for efficient methods for solving problems. How efficient can you be?

Can you find a way to identify times tables after they have been shifted up?

How could Penny, Tom and Matthew work out how many chocolates there are in different sized boxes?

Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?

Use your skill and knowledge to place various scientific lengths in order of size. Can you judge the length of objects with sizes ranging from 1 Angstrom to 1 million km with no wrong attempts?

Can you explain the surprising results Jo found when she calculated the difference between square numbers?

Use Farey sequences to obtain rational approximations to irrational numbers.

Investigate Farey sequences of ratios of Fibonacci numbers.

Can you find the maximum value of the curve defined by this expression?

How do you choose your planting levels to minimise the total loss at harvest time?

Small circles nestle under touching parent circles when they sit on the axis at neighbouring points in a Farey sequence.

Investigate the effects of the half-lifes of the isotopes of cobalt on the mass of a mystery lump of the element.

You found many different ways of finding the number on the reverse of the hundred square.

In this article Jenny talks about Assessing Pupils' Progress and the use of NRICH problems.

In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?

The first of three articles on the History of Trigonometry. This takes us from the Egyptians to early work on trigonometry in China.

This article sets some puzzles and describes how Euclid's algorithm and continued fractions are related.