Key to Percents first emphasizes mental computation and estimation skills--since most work with percents is done without pencil and paper. Then students are taught to solve percent problems using equal fractions and decimal multiplication. Finally, percents are used to solve word problems in a variety of applications. Key to Percents assumes only a knowledge of fraction and decimal computation. Book 1 covers Percent Concepts. Book 2 covers Percents and Fractions. Book 3 covers Percents and Decimals.