In this topic, students transition from thinking about ratio relationships in general to focusing on a special ratio relationship: percent. Students learn that a percent can be defi ned multiple ways: as a ratio; as a decimal to the hundredths place; and as a part-to-whole relationship in which the whole is 100. Students use their knowledge of fractions and decimals and their intuitive understanding of percents to write and compare rational numbers written in these three different forms. They complete number lines of common fractions, decimals, percent equivalences, connecting to prior work with benchmark fractions and decimals. Throughout this topic, students continue to develop their fl uency with whole numbers, fractions, decimals, area, and volume in the context of solving mathematical and real-world problems.