Ben and his mum are planting garlic. Use the interactivity to help you find out how many cloves of garlic they might have had.
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.
How many different rhythms can you make by putting two drums on the wheel?
Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.
Find out what a "fault-free" rectangle is and try to make some of your own.
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 find all the different ways of lining up these Cuisenaire rods?
What happens when you try and fit the triomino pieces into these two grids?
Can you cover the camel with these pieces?
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?
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?
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?
How many trains can you make which are the same length as Matt's, using rods that are identical?
Use the clues to colour each square.
Here are some rods that are different colours. How could I make a dark green rod using yellow and white rods?
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
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?
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?
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?
How many different triangles can you make on a circular pegboard that has nine pegs?
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?
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?
NRICH December 2006 advent calendar - a new tangram for each day in the run-up to Christmas.
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!
Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?
Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
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?
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?
How many different triangles can you draw on the dotty grid which each have one dot in the middle?
How many triangles can you make using sticks that are 3cm, 4cm and 5cm long?
Try out the lottery that is played in a far-away land. What is the chance of winning?
This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.
Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
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?
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....?
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?
Here is a chance to play a version of the classic Countdown Game.
Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.
Our 2008 Advent Calendar has a 'Making Maths' activity for every day in the run-up to Christmas.
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
Explore the different tunes you can make with these five gourds. What are the similarities and differences between the two tunes you are given?
Imagine a wheel with different markings painted on it at regular intervals. Can you predict the colour of the 18th mark? The 100th mark?
Arrange any number of counters from these 18 on the grid to make a rectangle. What numbers of counters make rectangles? How many different rectangles can you make with each number of counters?
Move just three of the circles so that the triangle faces in the opposite direction.
Yasmin and Zach have some bears to share. Which numbers of bears can they share so that there are none left over?