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?
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?
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10
Can you hang weights in the right place to make the equaliser
Place the numbers 1 to 6 in the circles so that each number is the
difference between the two numbers just below it.
Make one big triangle so the numbers that touch on the small triangles add to 10. You could use the interactivity to help you.
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?
Sort the houses in my street into different groups. Can you do it in any other ways?
Can you use the numbers on the dice to reach your end of the number line before your partner beats you?
Use the information about Sally and her brother to find out how many children there are in the Brown family.
If you have only four weights, where could you place them in order
to balance this equaliser?
Can you spot the similarities between this game and other games you know? The aim is to choose 3 numbers that total 15.
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?
Can you put the 25 coloured tiles into the 5 x 5 square so that no column, no row and no diagonal line have tiles of the same colour in them?
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?
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!
Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.
A game for 2 people that everybody knows. You can play with a
friend or online. If you play correctly you never lose!
A game to be played against the computer, or in groups. Pick a 7-digit number. A random digit is generated. What must you subract to remove the digit from your number? the first to zero wins.
A variant on the game Alquerque
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?
Place the numbers 1 to 10 in the circles so that each number is the
difference between the two numbers just below it.
Use the interactivities to fill in these Carroll diagrams. How do you know where to place the numbers?
There are three versions of this challenge. The idea is to change the colour of all the spots on the grid. Can you do it in fewer throws of the dice?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Choose a symbol to put into the number sentence.
First Connect Three game for an adult and child. Use the dice numbers and either addition or subtraction to get three numbers in a straight line.
The idea of this game is to add or subtract the two numbers on the dice and cover the result on the grid, trying to get a line of three. Are there some numbers that are good to aim for?
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?
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
Can you put the numbers 1 to 8 into the circles so that the four
calculations are correct?
Use the number weights to find different ways of balancing the equaliser.
You'll need two dice to play this game against a partner. Will Incey Wincey make it to the top of the drain pipe or the bottom of the drain pipe first?
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?
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?
A game for 2 people that can be played on line or with pens and paper. Combine your knowledege of coordinates with your skills of strategic thinking.
A game for 1 or 2 people. Use the interactive version, or play with friends. Try to round up as many counters as possible.
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.
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?
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 game for 2 players. Can be played online. One player has 1 red
counter, the other has 4 blue. The red counter needs to reach the
other side, and the blue needs to trap the red.
Using angular.js to bind inputs to outputs
A game for 2 players that can be played online. Players take it in turns to select a word from the 9 words given. The aim is to select all the occurrences of the same letter.
Exchange the positions of the two sets of counters in the least possible number of moves
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?
Incey Wincey Spider game for an adult and child. Will Incey get to the top of the drainpipe?
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?
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?