Lesson objective: Measure the difference in length between two objects.

This lesson helps to build fluency with measuring length difference. A centimeter ruler is used here because it supports directly measuring differences. This work develops students' understanding that length difference can be measured.

Students engage in Mathematical Practice 6 (Attending to precision) as they precisely measure differences in length.

**Key vocabulary:**

**Special materials needed:**

- centimeter rulers
- common classroom objects (See Game Directions in the Additional Materials tab for specifics.)
- folders