Percentages, growth and decay, and financial mathematics

By the end you’ll be able to

• Use decimal multipliers for percentage increase and decrease, and calculate percentage change and percentage profit or loss
• Solve reverse-percentage problems to find the original amount, e.g. a price after a 15% discount is £68
• Calculate simple interest, compound interest and depreciation, and use $A = P(1 + \frac{r}{100})^n$ for repeated percentage change, including finding $n$ by trial or iteration