You may also like

Prime Magic

Place the numbers 1, 2, 3,..., 9 one on each square of a 3 by 3 grid so that all the rows and columns add up to a prime number. How many different solutions can you find?

What Is Ziffle?

Can you work out what a ziffle is on the planet Zargon?

Shapes on the Playground

Sally and Ben were drawing shapes in chalk on the school playground. Can you work out what shapes each of them drew using the clues?


Age 7 to 11
Challenge Level


chocolateGeorge and Jim want to buy a chocolate bar.

George needs 2p more and Jim needs 50p more to buy it.

When they put their money together, it is still not enough to pay for the chocolate bar.


How much is the chocolate bar?

Why do this problem?

This problem supports children in calculating with money, while it also requires them to be systematic.

Possible approach

Playing with the problem for a few minutes and thinking about what the minimum price of the chocolate bar could be is a useful starting point. How can pupils convince each other that they have all the solutions? Although simultaneous equations seem to be appropriate they would just get in the way!

Key questions

Try with a few different amounts of money for the two children. Does this help you to solve the problem?
What is the least the chocolate bar could be?
How much does this mean each child would have?
Are there any more answers and how do you know?

Possible extension

Pupils could create their own challenge along similar lines.  You could give them the price of the chocolate bar and they have to create the 'clues' so that it can be worked out.

Possible support

You could suggest that learners try to record what they have tried in an organised way e.g. using a list or table.