Lesson objective: Apply estimating length concepts to solve a problem.

This lesson provides an opportunity for students to apply their knowledge and understanding of estimating lengths to a real-life situation. Students are asked to estimate the lengths of two race courses and compare the two to see which is longer.

Key Concept students will use:

- Estimating length by using benchmarks, mental images of units, and objects of known length.

Skills students will use:

- Know the approximate lengths of benchmarks (such as a finger joint is about 1 inch), and repeat them to estimate length.
- Mentally picture inches and repeat them to estimate length.
- Compare objects of known length to objects of unknown length to estimate length.

Students engage in Mathematical Practice 5 (Use appropriate tools strategically) as they estimate the different race paths by comparing them to benchmarks (dollar bills and finger joints), mental images of units (inches), and objects of known length (a 4-inch pencil).

**Key vocabulary: **