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. The study of integers begins here. First the rationale for negative numbers is discussed. This includes examples using signed (or directed) numbers in practical situations. The rules for adding integers are discovered using examples of travel on a north/south highway. Using the graphic representation of subtraction developed in Lesson 1, the rule for subtracting integers is developed. The order of operations is then applied to addition and subtraction of integers. Students will learn to compare, add and subtract integers, apply the rules for order of operations to problems involving the addition and subtraction of integers.