Lesson objective: Understand that some measurement tools may be more appropriate than others based on the task or object.

Students bring prior knowledge of measurement from 1.MD.A.2. This prior knowledge is extended to measurement using standard units as students explore the different systems and various tools. A conceptual challenge students may encounter is developing a benchmark length for choosing the most appropriate measurement tool.

The concept is developed through work with measurement tools, which provides students with opportunities to choose and use the various measurement tools appropriately.

This work helps students deepen their understanding of a number because, as students select the measurement tool, they must use it appropriately and correctly, and align the object with the tool to count the units from the beginning point to the end point of the object being measured.

Students engage in Mathematical Practice 5 (Use appropriate tools strategically) as they measure each item twice and determine the best tool to find the measured length of the object.

**Key vocabulary:**

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

**Special materials needed:**

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