Can you rank these sets of quantities in order, from smallest to largest? Can you provide convincing evidence for your rankings?

How many centimetres of rope will I need to make another mat just like the one I have here?

My measurements have got all jumbled up! Swap them around and see if you can find a combination where every measurement is valid.

A simple visual exploration into halving and doubling.

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

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

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.

Grandpa was measuring a rug using yards, feet and inches. Can you help William to work out its area?

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

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

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

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

Look at the mathematics that is all around us - this circular window is a wonderful example.

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

Can you draw a square in which the perimeter is numerically equal to the area?

Have a good look at these images. Can you describe what is happening? There are plenty more images like this on NRICH's Exploring Squares CD.

This article for teachers gives some food for thought when teaching ideas about area.

What shape has Harry drawn on this clock face? Can you find its area? What is the largest number of square tiles that could cover this area?

What is the total area of the four outside triangles which are outlined in red in this arrangement of squares inside each other?

Can you help the children find the two triangles which have the lengths of two sides numerically equal to their areas?

The area of a square inscribed in a circle with a unit radius is, satisfyingly, 2. What is the area of a regular hexagon inscribed in a circle with a unit radius?

Draw some isosceles triangles with an area of $9$cm$^2$ and a vertex at (20,20). If all the vertices must have whole number coordinates, how many is it possible to draw?

If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?

Read about David Hilbert who proved that any polygon could be cut up into a certain number of pieces that could be put back together to form any other polygon of equal area.

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?

Seven small rectangular pictures have one inch wide frames. The frames are removed and the pictures are fitted together like a jigsaw to make a rectangle of length 12 inches. Find the dimensions of. . . .

Choose a box and work out the smallest rectangle of paper needed to wrap it so that it is completely covered.

My local DIY shop calculates the price of its windows according to the area of glass and the length of frame used. Can you work out how they arrived at these prices?

In this game for two players, you throw two dice and find the product. How many shapes can you draw on the grid which have that area or perimeter?

How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?

You have pitched your tent (the red triangle) on an island. Can you move it to the position shown by the purple triangle making sure you obey the rules?

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

These practical challenges are all about making a 'tray' and covering it with paper.

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?

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

What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?

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

It is possible to dissect any square into smaller squares. What is the minimum number of squares a 13 by 13 square can be dissected into?

Use the information on these cards to draw the shape that is being described.

This practical challenge invites you to investigate the different squares you can make on a square geoboard or pegboard.

What can you say about these shapes? This problem challenges you to create shapes with different areas and perimeters.

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?

These rectangles have been torn. How many squares did each one have inside it before it was ripped?

A task which depends on members of the group noticing the needs of others and responding.

An activity for high-attaining learners which involves making a new cylinder from a cardboard tube.

Explore this interactivity and see if you can work out what it does. Could you use it to estimate the area of a shape?

How can you change the area of a shape but keep its perimeter the same? How can you change the perimeter but keep the area the same?

I'm thinking of a rectangle with an area of 24. What could its perimeter be?