Can you locate the lost giraffe? Input coordinates to help you search and find the giraffe in the fewest guesses.
A tilted square is a square with no horizontal sides. Can you devise a general instruction for the construction of a square when you are given just one of its sides?
When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...
Can you find a reliable strategy for choosing coordinates that will locate the robber in the minimum number of guesses?
Slide the pieces to move Khun Phaen past all the guards into the position on the right from which he can escape to freedom.
It's easy to work out the areas of most squares that we meet, but what if they were tilted?
A game for 2 players. Can be played online. One player has 1 red counter, the other has 4 blue. The red counter needs to reach the other side, and the blue needs to trap the red.
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.
Triangular numbers can be represented by a triangular array of squares. What do you notice about the sum of identical triangle numbers?
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
Start by putting one million (1 000 000) into the display of your calculator. Can you reduce this to 7 using just the 7 key and add, subtract, multiply, divide and equals as many times as you like?
Can you find a relationship between the number of dots on the circle and the number of steps that will ensure that all points are hit?
Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?
The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?
An animation that helps you understand the game of Nim.
How have the numbers been placed in this Carroll diagram? Which labels would you put on each row and column?
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?
What are the areas of these triangles? What do you notice? Can you generalise to other "families" of triangles?
Can you coach your rowing eight to win?
Could games evolve by natural selection? Take part in this web experiment to find out!
Can you beat the computer in the challenging strategy game?
Euler discussed whether or not it was possible to stroll around Koenigsberg crossing each of its seven bridges exactly once. Experiment with different numbers of islands and bridges.
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.
Starting with the number 180, take away 9 again and again, joining up the dots as you go. Watch out - don't join all the dots!
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. . . .
What are the coordinates of the coloured dots that mark out the tangram? Try changing the position of the origin. What happens to the coordinates now?
This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?
A game for 2 people that can be played on line or with pens and paper. Combine your knowledege of coordinates with your skills of strategic thinking.
Can you make a right-angled triangle on this peg-board by joining up three points round the edge?
Learn how to use the Shuffles interactivity by running through these tutorial demonstrations.
If you have only four weights, where could you place them in order to balance this equaliser?
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
Show how this pentagonal tile can be used to tile the plane and describe the transformations which map this pentagon to its images in the tiling.
Practise your diamond mining skills and your x,y coordination in this homage to Pacman.
Place the numbers from 1 to 9 in the squares below so that the difference between joined squares is odd. How many different ways can you do this?
Draw some isosceles triangles with an area of $9$cm$^2$ and a vertex at (20,20). If all the vertices must have whole number coordinates, how many is it possible to draw?
Can you complete this jigsaw of the multiplication square?
Help the bee to build a stack of blocks far enough to save his friend trapped in the tower.
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
7 balls are shaken in a container. You win if the two blue balls touch. What is the probability of winning?
Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?
Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.
Can you make the green spot travel through the tube by moving the yellow spot? Could you draw a tube that both spots would follow?
Can you explain the strategy for winning this game with any target?
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
Can you make a cycle of pairs that add to make a square number using all the numbers in the box below, once and once only?
First Connect Three game for an adult and child. Use the dice numbers and either addition or subtraction to get three numbers in a straight line.
Choose a symbol to put into the number sentence.
Here is a solitaire type environment for you to experiment with. Which targets can you reach?
What is the greatest number of squares you can make by overlapping three squares?