Dr Fishwick had five coins in his pocket but he didn’t tell us which coins they were. So how much money might he have? It had to be at least 5p but it could be as much as £10.

We worked systematically to see what amounts were possible. After a while we shared the task around the class so that we could find more answers before the end of the lesson. At the end we could make every amount from 5p up to 57p and had also found £1-£1.17, £1.50-£1.61 and £2-£2.10. Who knew five coins could give so many different answers?