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 put the numbers 1 to 8 into the circles so that the four calculations are correct?
Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
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?
Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.
Ben and his mum are planting garlic. Use the interactivity to help you find out how many cloves of garlic they might have had.
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?
Can you work out how to balance this equaliser? You can put more than one weight on a hook.
How many trains can you make which are the same length as Matt's, using rods that are identical?
Try out the lottery that is played in a far-away land. What is the chance of winning?
Can you find all the different ways of lining up these Cuisenaire rods?
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!
In your bank, you have three types of coins. The number of spots shows how much they are worth. Can you choose coins to exchange with the groups given to make the same total?
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?
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?
What happens when you try and fit the triomino pieces into these two grids?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Can you cover the camel with these pieces?
Use the clues to colour each square.
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 triangles can you make using sticks that are 3cm, 4cm and 5cm long?
Here are some rods that are different colours. How could I make a dark green rod using yellow and white rods?
Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.
Can you make a train the same length as Laura's but using three differently coloured rods? Is there only one way of doing it?
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?
If you have only four weights, where could you place them in order to balance this equaliser?
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
How many different triangles can you draw on the dotty grid which each have one dot in the middle?
How many different rhythms can you make by putting two drums on the wheel?
Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.
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?
How many different triangles can you make on a circular pegboard that has nine pegs?
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?
NRICH December 2006 advent calendar - a new tangram for each day in the run-up to Christmas.
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
If you hang two weights on one side of this balance, in how many different ways can you hang three weights on the other side for it to be balanced?
Find out how we can describe the "symmetries" of this triangle and investigate some combinations of rotating and flipping it.
Use the information about Sally and her brother to find out how many children there are in the Brown family.
Can you find all the different triangles on these peg boards, and find their angles?
Three beads are threaded on a circular wire and are coloured either red or blue. Can you find all four different combinations?
Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.
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?
A card pairing game involving knowledge of simple ratio.
An odd version of tic tac toe
Use your mouse to move the red and green parts of this disc. Can you make images which show the turnings described?
Take it in turns to place a domino on the grid. One to be placed horizontally and the other vertically. Can you make it impossible for your opponent to play?
A generic circular pegboard resource.
Move just three of the circles so that the triangle faces in the opposite direction.
Incey Wincey Spider game for an adult and child. Will Incey get to the top of the drainpipe?