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?
Here is a chance to play a version of the classic Countdown Game.
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!
If you have only four weights, where could you place them in order
to balance this equaliser?
Can you see why 2 by 2 could be 5? Can you predict what 2 by 10
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?
This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.
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?
Choose a symbol to put into the number sentence.
How have the numbers been placed in this Carroll diagram? Which
labels would you put on each row and column?
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?
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?
A game for 2 people that everybody knows. You can play with a
friend or online. If you play correctly you never lose!
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?
Place the numbers 1 to 10 in the circles so that each number is the
difference between the two numbers just below it.
Can you put the numbers 1 to 8 into the circles so that the four
calculations are correct?
Can you complete this jigsaw of the multiplication square?
Arrange the four number cards on the grid, according to the rules,
to make a diagonal, vertical or horizontal line.
Using angular.js to bind inputs to outputs
A card pairing game involving knowledge of simple ratio.
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
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?
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?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
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 spot the similarities between this game and other games you
know? The aim is to choose 3 numbers that total 15.
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 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.
An interactive activity for one to experiment with a tricky tessellation
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. . . .
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.
An environment which simulates working with Cuisenaire rods.
Use the sightings of the lion to guess the location of its lair.
Investigate the smallest number of moves it takes to turn these
mats upside-down if you can only turn exactly three at a time.
A game for 1 or 2 people. Use the interactive version, or play with friends. Try to round up as many counters as possible.
A train building game for 2 players.
Choose 13 spots on the grid. Can you work out the scoring system? What is the maximum possible score?
NRICH December 2006 advent calendar - a new tangram for each day in
the run-up to Christmas.
Find out what a "fault-free" rectangle is and try to make some of
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.
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
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?
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?
A game for 1 person to play on screen. Practise your number bonds
whilst improving your memory
Try to stop your opponent from being able to split the piles of counters into unequal numbers. Can you find a strategy?
Try entering different sets of numbers in the number pyramids. How does the total at the top change?
Imagine a wheel with different markings painted on it at regular
intervals. Can you predict the colour of the 18th mark? The 100th
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?
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?