The aim is to encourage students to practice calculating percentage change, but it will also help with basic arithmetic & finances. It should last an hour, including time for a quick starter, explanation, é a plenary discussion. Students are commodity traders looking to make as much profit as possible. There are six rounds and a 'newsflash&' each round, students should decide what to invest their $2000 in. The prices change by different percentages each round, so students will need to calculate these in order to find out how much revenue é therefore profit they have made.