Subtracting Rational Numbers

In this video lesson, students recognize that the difference between two numbers can be positive or negative, but the distance between two numbers is always positive. Using the geometry of the number line (MP7), they see that if you switch the order in which you subtract two numbers, the difference becomes its opposite. By observing the outcome of several examples, students conjecture that this is always true (MP8).

Grade 7, Episode 11: Unit 5, Lesson 6 | Illustrative Math