Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
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?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
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.
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?
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.
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?
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?
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?
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 six toy ladybirds into the box so that there are two ladybirds in every column and every row.
How have the numbers been placed in this Carroll diagram? Which labels would you put on each row and column?
Our 2008 Advent Calendar has a 'Making Maths' activity for every day in the run-up to Christmas.
Use the interactivities to fill in these Carroll diagrams. How do you know where to place the numbers?
A game for 2 people that everybody knows. You can play with a friend or online. If you play correctly you never lose!
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?
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?
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?
If you have only four weights, where could you place them in order to balance this equaliser?
Can you find all the different triangles on these peg boards, and find their angles?
The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?
How many different triangles can you make on a circular pegboard that has nine pegs?
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?
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....?
Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.
Can you put the numbers from 1 to 15 on the circles so that no consecutive numbers lie anywhere along a continuous straight line?
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!
Can you explain the strategy for winning this game with any target?
This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.
Try out the lottery that is played in a far-away land. What is the chance of winning?
NRICH December 2006 advent calendar - a new tangram for each day in the run-up to Christmas.
Can you find all the different ways of lining up these Cuisenaire rods?
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?
Choose a symbol to put into the number sentence.
Use the interactivity to investigate what kinds of triangles can be drawn on peg boards with different numbers of pegs.
Try to stop your opponent from being able to split the piles of counters into unequal numbers. Can you find a strategy?
Work out the fractions to match the cards with the same amount of money.
Carry out some time trials and gather some data to help you decide on the best training regime for your rowing crew.
A card pairing game involving knowledge of simple ratio.
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
Can you locate the lost giraffe? Input coordinates to help you search and find the giraffe in the fewest guesses.
A generic circular pegboard resource.
Triangular numbers can be represented by a triangular array of squares. What do you notice about the sum of identical triangle numbers?
Find out how we can describe the "symmetries" of this triangle and investigate some combinations of rotating and flipping it.
A and B are two interlocking cogwheels having p teeth and q teeth respectively. One tooth on B is painted red. Find the values of p and q for which the red tooth on B contacts every gap on the. . . .
An interactive game for 1 person. You are given a rectangle with 50 squares on it. Roll the dice to get a percentage between 2 and 100. How many squares is this? Keep going until you get 100. . . .