Can you each work out the number on your card? What do you notice? How could you sort the cards?
Take a rectangle of paper and fold it in half, and half again, to make four smaller rectangles. How many different ways can you fold it up?
Using different numbers of sticks, how many different triangles are you able to make? Can you make any rules about the numbers of sticks that make the most triangles?
NRICH December 2006 advent calendar - a new tangram for each day in the run-up to Christmas.
Can you make the birds from the egg tangram?
Can you make the most extraordinary, the most amazing, the most unusual patterns/designs from these triangles which are made in a special way?
What happens to the area of a square if you double the length of the sides? Try the same thing with rectangles, diamonds and other shapes. How do the four smaller ones fit into the larger one?
Arrange 9 red cubes, 9 blue cubes and 9 yellow cubes into a large 3 by 3 cube. No row or column of cubes must contain two cubes of the same colour.
How many triangles can you make on the 3 by 3 pegboard?
Make your own double-sided magic square. But can you complete both sides once you've made the pieces?
What is the greatest number of counters you can place on the grid below without four of them lying at the corners of a square?
Take 5 cubes of one colour and 2 of another colour. How many different ways can you join them if the 5 must touch the table and the 2 must not touch the table?
An activity making various patterns with 2 x 1 rectangular tiles.
In how many ways can you fit two of these yellow triangles together? Can you predict the number of ways two blue triangles can be fitted together?
Can you order pictures of the development of a frog from frogspawn and of a bean seed growing into a plant?
If these balls are put on a line with each ball touching the one in front and the one behind, which arrangement makes the shortest line of balls?
A group of children are discussing the height of a tall tree. How would you go about finding out its height?
These practical challenges are all about making a 'tray' and covering it with paper.
How many models can you find which obey these rules?
In this challenge, you will work in a group to investigate circular fences enclosing trees that are planted in square or triangular arrangements.
What is the smallest cuboid that you can put in this box so that you cannot fit another that's the same into it?
The ancient Egyptians were said to make right-angled triangles using a rope with twelve equal sections divided by knots. What other triangles could you make if you had a rope like this?
Our 2008 Advent Calendar has a 'Making Maths' activity for every day in the run-up to Christmas.
How can you put five cereal packets together to make different shapes if you must put them face-to-face?
Let's say you can only use two different lengths - 2 units and 4 units. Using just these 2 lengths as the edges how many different cuboids can you make?
How can you arrange the 5 cubes so that you need the smallest number of Brush Loads of paint to cover them? Try with other numbers of cubes as well.
This practical investigation invites you to make tessellating shapes in a similar way to the artist Escher.
We went to the cinema and decided to buy some bags of popcorn so we asked about the prices. Investigate how much popcorn each bag holds so find out which we might have bought.
Take a counter and surround it by a ring of other counters that MUST touch two others. How many are needed?
Can you recreate this Indian screen pattern? Can you make up similar patterns of your own?
Can you fit the tangram pieces into the outline of Wai Ping, Wah Ming and Chi Wing?
The challenge for you is to make a string of six (or more!) graded cubes.
Here is a solitaire type environment for you to experiment with. Which targets can you reach?
Delight your friends with this cunning trick! Can you explain how it works?
Follow the diagrams to make this patchwork piece, based on an octagon in a square.
Looking at the picture of this Jomista Mat, can you decribe what you see? Why not try and make one yourself?
This practical problem challenges you to create shapes and patterns with two different types of triangle. You could even try overlapping them.
Can you fit the tangram pieces into the outline of this junk?
Make new patterns from simple turning instructions. You can have a go using pencil and paper or with a floor robot.
Can you fit the tangram pieces into the outlines of these clocks?
Can you fit the tangram pieces into the outlines of these people?
Can you fit the tangram pieces into the outline of the child walking home from school?
Can you fit the tangram pieces into the outlines of the lobster, yacht and cyclist?
Can you fit the tangram pieces into the outlines of the chairs?
Can you fit the tangram pieces into the outline of this brazier for roasting chestnuts?
Can you fit the tangram pieces into the outline of Little Fung at the table?
Kaia is sure that her father has worn a particular tie twice a week in at least five of the last ten weeks, but her father disagrees. Who do you think is right?
Have a go at drawing these stars which use six points drawn around a circle. Perhaps you can create your own designs?
Can you fit the tangram pieces into the outline of this telephone?
Can you fit the tangram pieces into the outline of Little Ming playing the board game?