In this unit, we study rational numbers, which are numbers that can be written as a ratio of two integers. All fractions and whole numbers are rational numbers, and so are percents and decimals (except non-ending non-repeating decimals). Obviously, students already know a lot about rational numbers and how to calculate with them. Our focus in this unit is to extend that knowledge to negative fractions and negative decimals. The first lesson presents the definition of a rational number, how to co