Make and prove a conjecture about the cyclic quadrilateral inscribed in a circle of radius r that has the maximum perimeter and the maximum area.

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.

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.

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.

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

Re-arrange the pieces of the puzzle to form a rectangle and then to form an equilateral triangle. Calculate the angles and lengths.

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

Can you make a right-angled triangle on this peg-board by joining up three points round the edge?

A tool for generating random integers.

Match pairs of cards so that they have equivalent ratios.

This resource contains a range of problems and interactivities on the theme of coordinates in two and three dimensions.

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

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

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

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

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

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?

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a square.

A spherical balloon lies inside a wire frame. How much do you need to deflate it to remove it from the frame if it remains a sphere?

A metal puzzle which led to some mathematical questions.

Can you beat the computer in the challenging strategy game?

How good are you at finding the formula for a number pattern ?

Six circles around a central circle make a flower. Watch the flower as you change the radii in this circle packing. Prove that with the given ratios of the radii the petals touch and fit perfectly.

Use Excel to explore multiplication of fractions.

Can you locate these values on this interactive logarithmic scale?

Try this interactivity to familiarise yourself with the proof that the square root of 2 is irrational. Sort the steps of the proof into the correct order.

This resource contains interactive problems to support work on number sequences at Key Stage 4.

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?

An environment that enables you to investigate tessellations of regular polygons

Use Excel to practise adding and subtracting fractions.

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

The classic vector racing game brought to a screen near you.

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

An Excel spreadsheet with an investigation.

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

Use an Excel spreadsheet to explore long multiplication.

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

Use an interactive Excel spreadsheet to investigate factors and multiples.

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.

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

Square It game for an adult and child. Can you come up with a way of always winning this game?

Take any parallelogram and draw squares on the sides of the parallelogram. What can you prove about the quadrilateral formed by joining the centres of these squares?

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

How can we solve equations like 13x + 29y = 42 or 2x +4y = 13 with the solutions x and y being integers? Read this article to find out.