Show that for any triangle it is always possible to construct 3 touching circles with centres at the vertices. Is it possible to construct touching circles centred at the vertices of any polygon?

To avoid losing think of another very well known game where the patterns of play are similar.

A right-angled isosceles triangle is rotated about the centre point of a square. What can you say about the area of the part of the square covered by the triangle as it rotates?

A metal puzzle which led to some mathematical questions.

If you continue the pattern, can you predict what each of the following areas will be? Try to explain your prediction.

Do you know how to find the area of a triangle? You can count the squares. What happens if we turn the triangle on end? Press the button and see. Try counting the number of units in the triangle now. . . .

A collection of resources to support work on Factors and Multiples at Secondary level.

A group of interactive resources to support work on percentages Key Stage 4.

Use Excel to investigate the effect of translations around a number grid.

Can you give the coordinates of the vertices of the fifth point in the patterm on this 3D grid?

Triangle ABC has equilateral triangles drawn on its edges. Points P, Q and R are the centres of the equilateral triangles. What can you prove about the triangle PQR?

Use Excel to explore multiplication of fractions.

Help the bee to build a stack of blocks far enough to save his friend trapped in the tower.

This set of resources for teachers offers interactive environments to support work on loci at Key Stage 4.

Can you beat the computer in the challenging strategy game?

An environment that enables you to investigate tessellations of regular polygons

Discover a handy way to describe reorderings and solve our anagram in the process.

What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?

The interactive diagram has two labelled points, A and B. It is designed to be used with the problem "Cushion Ball"

You can move the 4 pieces of the jigsaw and fit them into both outlines. Explain what has happened to the missing one unit of area.

Match the cards of the same value.

There are 27 small cubes in a 3 x 3 x 3 cube, 54 faces being visible at any one time. Is it possible to reorganise these cubes so that by dipping the large cube into a pot of paint three times you. . . .

The aim of the game is to slide the green square from the top right hand corner to the bottom left hand corner in the least number of moves.

Match pairs of cards so that they have equivalent ratios.

Use an interactive Excel spreadsheet to explore number in this exciting game!

Can you put the 25 coloured tiles into the 5 x 5 square so that no column, no row and no diagonal line have tiles of the same colour in them?

This game challenges you to locate hidden triangles in The White Box by firing rays and observing where the rays exit the Box.

A counter is placed in the bottom right hand corner of a grid. You toss a coin and move the star according to the following rules: ... What is the probability that you end up in the top left-hand. . . .

A tool for generating random integers.

A simple file for the Interactive whiteboard or PC screen, demonstrating equivalent fractions.

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

A simple spinner that is equally likely to land on Red or Black. Useful if tossing a coin, dropping it, and rummaging about on the floor have lost their appeal. Needs a modern browser; if IE then at. . . .

Use an Excel to investigate division. Explore the relationships between the process elements using an interactive spreadsheet.

This is an interactivity in which you have to sort the steps in the completion of the square into the correct order to prove the formula for the solutions of quadratic equations.

A circle rolls around the outside edge of a square so that its circumference always touches the edge of the square. Can you describe the locus of the centre of the circle?

P is a point on the circumference of a circle radius r which rolls, without slipping, inside a circle of radius 2r. What is the locus of P?

Here is a chance to play a fractions version of the classic Countdown Game.

An environment that simulates a protractor carrying a right- angled triangle of unit hypotenuse.

Start with any number of counters in any number of piles. 2 players take it in turns to remove any number of counters from a single pile. The winner is the player to take the last counter.

An Excel spreadsheet with an investigation.

Use Excel to practise adding and subtracting fractions.

Use an Excel spreadsheet to explore long multiplication.

A java applet that takes you through the steps needed to solve a Diophantine equation of the form Px+Qy=1 using Euclid's algorithm.

Use an interactive Excel spreadsheet to investigate factors and multiples.

This rectangle is cut into five pieces which fit exactly into a triangular outline and also into a square outline where the triangle, the rectangle and the square have equal areas.

We can show that (x + 1)² = x² + 2x + 1 by considering the area of an (x + 1) by (x + 1) square. Show in a similar way that (x + 2)² = x² + 4x + 4

A and B are two interlocking cogwheels having p teeth and q teeth respectively. One tooth on B is painted red. Find the values of p and q for which the red tooth on B contacts every gap on the. . . .

Find all the ways of placing the numbers 1 to 9 on a W shape, with 3 numbers on each leg, so that each set of 3 numbers has the same total.