Investigate how this pattern of squares continues. You could measure lengths, areas and angles.

I cut this square into two different shapes. What can you say about the relationship between them?

Here are many ideas for you to investigate - all linked with the number 2000.

This article for teachers suggests ideas for activities built around 10 and 2010.

Investigate the area of 'slices' cut off this cube of cheese. What would happen if you had different-sized block of cheese to start with?

What do these two triangles have in common? How are they related?

If I use 12 green tiles to represent my lawn, how many different ways could I arrange them? How many border tiles would I need each time?

Investigate these hexagons drawn from different sized equilateral triangles.

Investigate and explain the patterns that you see from recording just the units digits of numbers in the times tables.

What is the largest cuboid you can wrap in an A3 sheet of paper?

Follow the directions for circling numbers in the matrix. Add all the circled numbers together. Note your answer. Try again with a different starting number. What do you notice?

What is the largest number of circles we can fit into the frame without them overlapping? How do you know? What will happen if you try the other shapes?

Investigate the numbers that come up on a die as you roll it in the direction of north, south, east and west, without going over the path it's already made.

Investigate the different ways these aliens count in this challenge. You could start by thinking about how each of them would write our number 7.

The red ring is inside the blue ring in this picture. Can you rearrange the rings in different ways? Perhaps you can overlap them or put one outside another?

Bernard Bagnall describes how to get more out of some favourite NRICH investigations.

This activity asks you to collect information about the birds you see in the garden. Are there patterns in the data or do the birds seem to visit randomly?

Can you find out how the 6-triangle shape is transformed in these tessellations? Will the tessellations go on for ever? Why or why not?

A thoughtful shepherd used bales of straw to protect the area around his lambs. Explore how you can arrange the bales.

In my local town there are three supermarkets which each has a special deal on some products. If you bought all your shopping in one shop, where would be the cheapest?

Can you continue this pattern of triangles and begin to predict how many sticks are used for each new "layer"?

Here is your chance to investigate the number 28 using shapes, cubes ... in fact anything at all.

While we were sorting some papers we found 3 strange sheets which seemed to come from small books but there were page numbers at the foot of each page. Did the pages come from the same book?

Why does the tower look a different size in each of these pictures?

Take a look at these data collected by children in 1986 as part of the Domesday Project. What do they tell you? What do you think about the way they are presented?

Polygonal numbers are those that are arranged in shapes as they enlarge. Explore the polygonal numbers drawn here.

A group of children are discussing the height of a tall tree. How would you go about finding out its height?

This problem is intended to get children to look really hard at something they will see many times in the next few months.

This challenge asks you to investigate the total number of cards that would be sent if four children send one to all three others. How many would be sent if there were five children? Six?

Can you make these equilateral triangles fit together to cover the paper without any gaps between them? Can you tessellate isosceles triangles?

Arrange your fences to make the largest rectangular space you can. Try with four fences, then five, then six etc.

Investigate the number of faces you can see when you arrange three cubes in different ways.

Compare the numbers of particular tiles in one or all of these three designs, inspired by the floor tiles of a church in Cambridge.

Bernard Bagnall looks at what 'problem solving' might really mean in the context of primary classrooms.

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?

When Charlie asked his grandmother how old she is, he didn't get a straightforward reply! Can you work out how old she is?

These pictures were made by starting with a square, finding the half-way point on each side and joining those points up. You could investigate your own starting shape.

In this investigation we are going to count the number of 1s, 2s, 3s etc in numbers. Can you predict what will happen?

Investigate what happens when you add house numbers along a street in different ways.

Investigate the different ways you could split up these rooms so that you have double the number.

What is the smallest cuboid that you can put in this box so that you cannot fit another that's the same into it?

Explore ways of colouring this set of triangles. Can you make symmetrical patterns?

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?

Sort the houses in my street into different groups. Can you do it in any other ways?

I like to walk along the cracks of the paving stones, but not the outside edge of the path itself. How many different routes can you find for me to take?

An activity making various patterns with 2 x 1 rectangular tiles.

Try continuing these patterns made from triangles. Can you create your own repeating pattern?

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?

Can you find ways of joining cubes together so that 28 faces are visible?