Lesson objective: Add integers using the idea of distance and direction.

This lesson helps to build procedural skill with adding integers. The number line is used here because it supports students in thinking about the sign of a number indicating direction, and that there are two numbers a given distance from the first addend. This work develops students' understanding that we can think of adding with integers in the same way we think about adding positive rational numbers, by combining lengths. The new idea to consider is that the length or distance may be in the same or different direction as the starting addend.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they use the structure of addition that they know from working with positive numbers and the structure of the number line to practice representing sums of integers.

**Key vocabulary:**

**Special materials needed:**

- Blank number lines (optional)