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 see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?
If you have only four weights, where could you place them in order to balance this equaliser?
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?
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?
Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
Here is a chance to play a version of the classic Countdown Game.
Find out what a "fault-free" rectangle is and try to make some of your own.
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?
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
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?
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?
Place six toy ladybirds into the box so that there are two ladybirds in every column and every row.
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?
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?
Can you put the numbers 1 to 8 into the circles so that the four calculations are correct?
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!
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?
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?
Explore the different tunes you can make with these five gourds. What are the similarities and differences between the two tunes you are given?
Choose a symbol to put into the number sentence.
This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.
Our 2008 Advent Calendar has a 'Making Maths' activity for every day in the run-up to Christmas.
NRICH December 2006 advent calendar - a new tangram for each 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.
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....?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Try out the lottery that is played in a far-away land. What is the chance of winning?
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?
Can you explain the strategy for winning this game with any target?
An environment which simulates working with Cuisenaire rods.
Use the interactivity to play two of the bells in a pattern. How do you know when it is your turn to ring, and how do you know which bell to ring?
Can you fit the tangram pieces into the outline of Wai Ping, Wah Ming and Chi Wing?
Use the interactivity to investigate what kinds of triangles can be drawn on peg boards with different numbers of pegs.
Can you fit the tangram pieces into the outline of Mai Ling?
Three beads are threaded on a circular wire and are coloured either red or blue. Can you find all four different combinations?
A generic circular pegboard resource.
Can you fit the tangram pieces into the outlines of the candle and sundial?
How have the numbers been placed in this Carroll diagram? Which labels would you put on each row and column?
Work out the fractions to match the cards with the same amount of money.
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!
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 fit the tangram pieces into the outlines of the lobster, yacht and cyclist?
Can you fit the tangram pieces into the outline of the child walking home from school?
Can you fit the tangram pieces into the outlines of the chairs?
Can you fit the tangram pieces into the outline of Little Fung at the table?
Can you fit the tangram pieces into the outline of this telephone?
Can you fit the tangram pieces into the outlines of these clocks?
Can you fit the tangram pieces into the outline of Granma T?