Lesson objective: Relate unit size to the number of units needed in a measured length.

This lesson helps to build fluency with measurement relationships. A discussion of an example is used here because it highlights the connection between unit size and measured length. This work develops students' understanding that there is an inverse relationship between the size of a unit of measurement and the number of those units it takes to equal a given length.

Students engage in Mathematical Practice 2 (Reason abstractly and quantitatively) as they use measurement tools to better understand the relationship and connections to real-life applications.

**Key vocabulary: **

- foot
- inch
- inverse
- length
- meter
- meter stick
- relationship
- ruler
- tape measure
- tool
- unit of measure
- yard
- yardstick

**Special materials needed:**

- centimeter ruler
- inch ruler
- meter stick
- ruler
- tape measure
- yardstick