A percentages and interest Project suitable for KS3 and GCSE students. Topics: Compound Interest. Percentage change. Problem solving. A practical project that is ideally suited for Year 9, Year 10, and Year 11 classes. It has been popular, especially with the boys. I combined it with lessons on how to calculate taxes and the costs of living in an apartment as a theme about moving out of the home on their own. I would have the students move around in groups analysing the information.