Hover your mouse over the counters to see which ones will be removed. Click to remover them. The winner is the last one to remove a counter. How you can make sure you win?
Here are some rods that are different colours. How could I make a dark green rod using yellow and white rods?
Take a rectangle of paper and fold it in half, and half again, to make four smaller rectangles. How many different ways can you fold it up?
A tetromino is made up of four squares joined edge to edge. Can this tetromino, together with 15 copies of itself, be used to cover an eight by eight chessboard?
Use the clues to colour each square.
What happens when you try and fit the triomino pieces into these two grids?
Can you cover the camel with these pieces?
Arrange 9 red cubes, 9 blue cubes and 9 yellow cubes into a large 3 by 3 cube. No row or column of cubes must contain two cubes of the same colour.
What is the best way to shunt these carriages so that each train can continue its journey?
How many models can you find which obey these rules?
You have 4 red and 5 blue counters. How many ways can they be placed on a 3 by 3 grid so that all the rows columns and diagonals have an even number of red counters?
10 space travellers are waiting to board their spaceships. There are two rows of seats in the waiting room. Using the rules, where are they all sitting? Can you find all the possible ways?
If you split the square into these two pieces, it is possible to fit the pieces together again to make a new shape. How many new shapes can you make?
Can you shunt the trucks so that the Cattle truck and the Sheep truck change places and the Engine is back on the main line?
What is the greatest number of counters you can place on the grid below without four of them lying at the corners of a square?
How many different rhythms can you make by putting two drums on the wheel?
Design an arrangement of display boards in the school hall which fits the requirements of different people.
Take 5 cubes of one colour and 2 of another colour. How many different ways can you join them if the 5 must touch the table and the 2 must not touch the table?
Can you work out how many cubes were used to make this open box? What size of open box could you make if you had 112 cubes?
Can you work out how to balance this equaliser? You can put more than one weight on a hook.
Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.
Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.
Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.
Find your way through the grid starting at 2 and following these operations. What number do you end on?
Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?
Swap the stars with the moons, using only knights' moves (as on a chess board). What is the smallest number of moves possible?
A Sudoku with clues given as sums of entries.
This problem focuses on Dienes' Logiblocs. What is the same and what is different about these pairs of shapes? Can you describe the shapes in the picture?
Ben and his mum are planting garlic. Use the interactivity to help you find out how many cloves of garlic they might have had.
This task, written for the National Young Mathematicians' Award 2016, involves open-topped boxes made with interlocking cubes. Explore the number of units of paint that are needed to cover the boxes. . . .
Is it possible to place 2 counters on the 3 by 3 grid so that there is an even number of counters in every row and every column? How about if you have 3 counters or 4 counters or....?
How many different triangles can you draw on the dotty grid which each have one dot in the middle?
Make your own double-sided magic square. But can you complete both sides once you've made the pieces?
A dog is looking for a good place to bury his bone. Can you work out where he started and ended in each case? What possible routes could he have taken?
Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
How many triangles can you make using sticks that are 3cm, 4cm and 5cm long?
How many different ways can you find of fitting five hexagons together? How will you know you have found all the ways?
How many different triangles can you make on a circular pegboard that has nine pegs?
How can you arrange the 5 cubes so that you need the smallest number of Brush Loads of paint to cover them? Try with other numbers of cubes as well.
Using different numbers of sticks, how many different triangles are you able to make? Can you make any rules about the numbers of sticks that make the most triangles?
These practical challenges are all about making a 'tray' and covering it with paper.
An activity making various patterns with 2 x 1 rectangular tiles.
In how many ways can you fit two of these yellow triangles together? Can you predict the number of ways two blue triangles can be fitted together?
How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?
Cut four triangles from a square as shown in the picture. How many different shapes can you make by fitting the four triangles back together?
How many trains can you make which are the same length as Matt's, using rods that are identical?
Can you find all the different ways of lining up these Cuisenaire rods?
Building up a simple Celtic knot. Try the interactivity or download the cards or have a go on squared paper.
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
How many shapes can you build from three red and two green cubes? Can you use what you've found out to predict the number for four red and two green?