Exploring maths through problem solving

Problem of the Week

Cookies Cubed

Each of these trays has the same number of cookies on it. How many cookies would you need to eat to leave a cubed number of cookies?

Answer:

There are 3 trays of 12 cookies, so 36 cookies in total.
3×3×3=27
36-27=9

So, you need to eat 9 of the 36 cookies to leave 27 cookies (which is 3 cubed).

The image shows how useful visualisation can be. For the 3 x 3 x 3 you can 'see' the answer is 9, rather than calculate 3 x 4 x 3 = 36 and then find the difference between 36 and 27.

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