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?

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

A challenging activity focusing on finding all possible ways of stacking rods.

Numbers arranged in a square but some exceptional spatial awareness probably needed.

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

What is the smallest number of tiles needed to tile this patio? Can you investigate patios of different sizes?

Investigate all the different squares you can make on this 5 by 5 grid by making your starting side go from the bottom left hand point. Can you find out the areas of all these squares?

How many ways can you find of tiling the square patio, using square tiles of different sizes?

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

How will you decide which way of flipping over and/or turning the grid will give you the highest total?

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?

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

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

How many different ways can you find of fitting five hexagons together? How will you know you have found all the ways?

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

An investigation that gives you the opportunity to make and justify predictions.

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.

A description of some experiments in which you can make discoveries about triangles.

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.

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?

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

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

"Ip dip sky blue! Who's 'it'? It's you!" Where would you position yourself so that you are 'it' if there are two players? Three players ...?

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 shaped bracelets you could make from 18 different spherical beads. How do they compare if you use 24 beads?

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?

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?

Cut differently-sized square corners from a square piece of paper to make boxes without lids. Do they all have the same volume?

If we had 16 light bars which digital numbers could we make? How will you know you've found them all?

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

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

Place four pebbles on the sand in the form of a square. Keep adding as few pebbles as necessary to double the area. How many extra pebbles are added each time?

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?

Use the interactivity to find all the different right-angled triangles you can make by just moving one corner of the starting triangle.

Which times on a digital clock have a line of symmetry? Which look the same upside-down? You might like to try this investigation and find out!

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

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

Start with four numbers at the corners of a square and put the total of two corners in the middle of that side. Keep going... Can you estimate what the size of the last four numbers will be?

In how many ways can you stack these rods, following the rules?

The challenge here is to find as many routes as you can for a fence to go so that this town is divided up into two halves, each with 8 blocks.

You cannot choose a selection of ice cream flavours that includes totally what someone has already chosen. Have a go and find all the different ways in which seven children can have ice cream.

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

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

A follow-up activity to Tiles in the Garden.

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?

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

There are three tables in a room with blocks of chocolate on each. Where would be the best place for each child in the class to sit if they came in one at a time?

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

If you have three circular objects, you could arrange them so that they are separate, touching, overlapping or inside each other. Can you investigate all the different possibilities?