Here is a chance to play a version of the classic Countdown Game.
This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.
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?
Can you complete this jigsaw of the multiplication square?
Can you find a relationship between the number of dots on the
circle and the number of steps that will ensure that all points are
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10
How have the numbers been placed in this Carroll diagram? Which
labels would you put on each row and column?
If you have only four weights, where could you place them in order
to balance this equaliser?
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?
Imagine a wheel with different markings painted on it at regular
intervals. Can you predict the colour of the 18th mark? The 100th
An environment which simulates working with Cuisenaire rods.
A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.
Arrange the four number cards on the grid, according to the rules,
to make a diagonal, vertical or horizontal line.
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?
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?
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!
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 put the numbers from 1 to 15 on the circles so that no
consecutive numbers lie anywhere along a continuous straight line?
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?
Choose 13 spots on the grid. Can you work out the scoring system? What is the maximum possible score?
A game for 2 people that everybody knows. You can play with a
friend or online. If you play correctly you never lose!
What are the coordinates of the coloured dots that mark out the
tangram? Try changing the position of the origin. What happens to
the coordinates now?
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
Investigate which numbers make these lights come on. What is the smallest number you can find that lights up all the lights?
Work out how to light up the single light. What's the rule?
Try out the lottery that is played in a far-away land. What is the
chance of winning?
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?
Investigate how the four L-shapes fit together to make an enlarged
L-shape. You could explore this idea with other shapes too.
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?
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.
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!
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. . . .
In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?
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.
Investigate the smallest number of moves it takes to turn these
mats upside-down if you can only turn exactly three at a time.
An interactive activity for one to experiment with a tricky tessellation
Use the interactivity to find all the different right-angled
triangles you can make by just moving one corner of the starting
Using angular.js to bind inputs to outputs
A card pairing game involving knowledge of simple ratio.
Can you put the numbers 1 to 8 into the circles so that the four
calculations are correct?
Use the interactivity to create some steady rhythms. How could you
create a rhythm which sounds the same forwards as it does
Can you find all the different ways of lining up these Cuisenaire
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?
Ahmed has some wooden planks to use for three sides of a rabbit run
against the shed. What quadrilaterals would he be able to make with
the planks of different lengths?
This 100 square jigsaw is written in code. It starts with 1 and
ends with 100. Can you build it up?
Find out what a "fault-free" rectangle is and try to make some of
NRICH December 2006 advent calendar - a new tangram for each day in
the run-up to Christmas.
Place the numbers 1 to 10 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.