Hi Sir, Thank you for showing us how to calculate to the fourth root, however you didn’t mention how to calculate to the fifth root if five years is given in the exam. Would it then be a matter of calculating to the third root and then to the second root? Or calculating to the second root first and then the third root second? Or is there another way? Thanks for your help and quick response as exam is only 3 weeks away 🙂 Sonria.