This award-winning series helps students to build confidence in their ability to "do math" and develop the knowledge and skills required to become mathematically literate. This lesson introduces ratios using three types of problems. First the concept of ratio is investigated and how ratios are related to fractions. Then methods of solving proportions are discussed. The third problem uses proportions to offer an alternative method for solving percentage problems. Students will learn to write equivalent ratios and solve proportions, while being able to explain why cross-multiplying works in solving proportions.