Math

Math guides walk through everyday percentage and money calculations step by step, so you can do them by hand or check a calculator’s answer. Read how to calculate a percentage increase for the change between two numbers, how to calculate a discount for sale prices and stacked offers, and how to calculate a tip for splitting a bill.

Each guide gives the formula first, then a worked example with real numbers, then the mistakes people make most often, such as adding two percentage discounts together instead of applying them one after the other.

When you want the answer quickly, use the matching percentage calculator, discount calculator or tip calculator. More tools for fractions, ratios, rounding and geometry are in the everyday math topic. The guides are written for adults and students who want to understand the method as well as the result.