How many different ways can you find to join three equilateral
triangles together? Can you convince us that you have found them
How many trains can you make which are the same length as Matt's,
using rods that are identical?
How many different triangles can you draw on the dotty grid which each have one dot in the middle?
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?
Use the clues to colour each square.
How many triangles can you make using sticks that are 3cm, 4cm and 5cm long?
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
Here are some rods that are different colours. How could I make a dark green rod using yellow and white rods?
How many different triangles can you make on a circular pegboard
that has nine pegs?
Can you work out how to balance this equaliser? You can put more
than one weight on a hook.
Use the interactivity to help get a feel for this problem and to find out all the possible ways the balls could land.
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?
Cut four triangles from a square as shown in the picture. How many
different shapes can you make by fitting the four triangles back
Place six toy ladybirds into the box so that there are two
ladybirds in every column and every row.
Investigate the smallest number of moves it takes to turn these
mats upside-down if you can only turn exactly three at a time.
What happens when you try and fit the triomino pieces into these
Can you cover the camel with these pieces?
Ben and his mum are planting garlic. Use the interactivity to help
you find out how many cloves of garlic they might have had.
Place the numbers 1 to 6 in the circles so that each number is the
difference between the two numbers just below it.
How many different rhythms can you make by putting two drums on the
If you can post the triangle with either the blue or yellow colour face up, how many ways can it be posted altogether?
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?
Arrange the four number cards on the grid, according to the rules,
to make a diagonal, vertical or horizontal line.
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....?
Three beads are threaded on a circular wire and are coloured either red or blue. Can you find all four different combinations?
This 100 square jigsaw is written in code. It starts with 1 and
ends with 100. Can you build it up?
Use the information about Sally and her brother to find out how many children there are in the Brown family.
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?
Use the interactivity to find all the different right-angled
triangles you can make by just moving one corner of the starting
Can you hang weights in the right place to make the equaliser
Try out the lottery that is played in a far-away land. What is the
chance of winning?
Make one big triangle so the numbers that touch on the small triangles add to 10. You could use the interactivity to help you.
Find out how we can describe the "symmetries" of this triangle and
investigate some combinations of rotating and flipping it.
Can you put the numbers 1 to 8 into the circles so that the four
calculations are correct?
Find out what a "fault-free" rectangle is and try to make some of
Can you put the numbers from 1 to 15 on the circles so that no
consecutive numbers lie anywhere along a continuous straight 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?
Our 2008 Advent Calendar has a 'Making Maths' activity for every
day in the run-up to Christmas.
Investigate the different sounds you can make by putting the owls
and donkeys on the wheel.
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?
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 find all the different ways of lining up these Cuisenaire
Can you find all the different triangles on these peg boards, and
find their angles?
Use your mouse to move the red and green parts of this disc. Can
you make images which show the turnings described?
Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Sort the houses in my street into different groups. Can you do it in any other ways?
Explore the different tunes you can make with these five gourds.
What are the similarities and differences between the two tunes you
NRICH December 2006 advent calendar - a new tangram for each day in
the run-up to Christmas.