Lesson objective: Fluently locate opposite numbers on a number line.

This lesson helps to build fluency with opposite numbers. Number lines are used because they show, visually, the relationship opposite numbers have to 0 and to each other. This work develops students' understanding that because the number line can show both distance and direction, we can locate the opposite of any rational number on the number line. It also develops the understanding that the absolute values of a rational number and its opposite are equivalent.

Students engage in Mathematical Practice 2 (reason abstractly and quantitatively) and 4 (model with mathematics) as they plot rational numbers on number lines in order to compare opposite numbers.

**Key vocabulary:**

- rational number
- integer
- opposite
- number line
- order
- compare