Digit Dog has got a 3 x 3 grid and 9 Numicon shapes – 3 one shapes, 3 two shapes and 3 three shapes. He is going to put the shapes on the grid and investigate the totals he can make.

This is what he does first:

Copy what Digit Dog has done.

Digit Dog says that the sum of the shapes in the first row is 6. *Do you agree with Digit Dog? Why or why not? Are you sure? *

Expecting learners to explain their thinking helps develop their reasoning skills.

*If you agree, convince me that Digit Dog is correct. If you don’t agree, explain why you think he is wrong.*

Encourage learners to explain why the total of the first row is 6. Use the *Numicon* shapes to show that the 3 shapes in the first row are equivalent to a six-shape. Explanations are much easier when you use concrete apparatus.

Use the pan balance to explain.

Calculating Cat says that the total of the shapes in the third column is 6 too. *Is she right? How do you know? *

*What is the same and what is different about Digit Dog’s row and Calculating Cat’s column?*

*Can you find any other rows or columns that total 6? Are there any that total more than 6? What about less than 6?*

*Can you find a row or column that totals 1 more than 6? What about 1 less than 6?*

*What else do you notice?*

*How are you going to record the totals you have found?*

Now arrange the shapes in any way you want and investigate the totals that you make. *What do you notice? What is the largest total you can make? The smallest total?*

Look at a grid your friend has done. *What is the same? What is different?*

*What if you used other shapes?*

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