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If you are a teacher, click here for a version of the problem suitable for classroom use, together with supporting materials. Otherwise, read on...

Each symbol has a numerical value. The total for the symbols is written at the end of each row and column.

Can you find the missing total that should go where the question mark has been put?

 
There is a lot of information in the grid, so you will need to make some choices about what to focus on first. Click below to see some images that draw your attention to particular parts of the grid.

What can you deduce from each image?
 
 
Image 1
 
 
 

Image 2
 
 

Image 3
 
 

Image 4
 
 

Image 5
 
 

Image 6
 
 
Can you find any other ways of solving the problem?
 
 
You can apply these strategies to other versions of the problem. You could use the interactivity Fruity Totals to generate lots of different examples and to practise your strategies.
 
You may be interested in the other problems in our Reflecting on Methods, Improving Solutions Feature.

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Geoboards

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

Polydron

This activity investigates how you might make squares and pentominoes from Polydron.

Multilink Cubes

If you had 36 cubes, what different cuboids could you make?

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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