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?
This was a problem for our birthday website. Can you use four of these pieces to form a square? How about making a square with all five pieces?
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
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?
NRICH December 2006 advent calendar - a new tangram for each day in the run-up to Christmas.
Our 2008 Advent Calendar has a 'Making Maths' activity for every day in the run-up to Christmas.
Can you find all the different ways of lining up these Cuisenaire rods?
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?
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?
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
Investigate the smallest number of moves it takes to turn these mats upside-down if you can only turn exactly three at a time.
Can you find all the different triangles on these peg boards, and find their angles?
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 everybody knows. You can play with a friend or online. If you play correctly you never lose!
Find out how we can describe the "symmetries" of this triangle and investigate some combinations of rotating and flipping it.
Choose a symbol to put into the number sentence.
Three beads are threaded on a circular wire and are coloured either red or blue. Can you find all four different combinations?
What shaped overlaps can you make with two circles which are the same size? What shapes are 'left over'? What shapes can you make when the circles are different sizes?
Try out the lottery that is played in a far-away land. What is the chance of winning?
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!
How many different triangles can you make on a circular pegboard that has nine pegs?
What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?
There are nine teddies in Teddy Town - three red, three blue and three yellow. There are also nine houses, three of each colour. Can you put them on the map of Teddy Town according to the rules?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Find out what a "fault-free" rectangle is and try to make some of your own.
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....?
A generic circular pegboard resource.
Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
What shape is the overlap when you slide one of these shapes half way across another? Can you picture it in your head? Use the interactivity to check your visualisation.
Board Block game for two. Can you stop your partner from being able to make a shape on the board?
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 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.
An interactive game to be played on your own or with friends. Imagine you are having a party. Each person takes it in turns to stand behind the chair where they will get the most chocolate.
Work out the fractions to match the cards with the same amount of money.
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?
Explore the different tunes you can make with these five gourds. What are the similarities and differences between the two tunes you are given?
Use the interactivity to make this Islamic star and cross design. Can you produce a tessellation of regular octagons with two different types of triangle?
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?
A card pairing game involving knowledge of simple ratio.
Use the interactivity to investigate what kinds of triangles can be drawn on peg boards with different numbers of pegs.
How can the same pieces of the tangram make this bowl before and after it was chipped? Use the interactivity to try and work out what is going on!
Use the interactivity or play this dice game yourself. How could you make it fair?
Ahmed has some wooden planks to use for three sides of a rabbit run against the shed. What quadrilaterals would he be able to make with the planks of different lengths?
Investigate how the four L-shapes fit together to make an enlarged L-shape. You could explore this idea with other shapes too.
Can you work out what is wrong with the cogs on a UK 2 pound coin?
Imagine a wheel with different markings painted on it at regular intervals. Can you predict the colour of the 18th mark? The 100th mark?
A shape and space game for 2,3 or 4 players. Be the last person to be able to place a pentomino piece on the playing board. Play with card, or on the computer.
Can you fit the tangram pieces into the outline of Little Fung at the table?