This document provides an introduction to and examples of using direct and indirect rules of three to solve proportional reasoning problems. It begins by defining rules of three as a way to solve problems with some known data and an unknown variable. Direct proportion means that if one variable increases, the other also increases. Indirect proportion means that if one variable increases, the other decreases. Four example problems from administration and economics are then presented and solved using direct and indirect rules of three. The document concludes by citing references used.