Lesson objective: Solve problems that apply skills in converting metric measurement units from greater to smaller units by multiplying, or smaller to greater units by dividing.

This lesson provides an opportunity for students to apply their knowledge and understanding of metric measurement conversion. Students are asked to determine the best buy of jewelry cord. The cord is sold at several different costs and is packaged in several different measurement units.

Key Concept students will use:

- The attribute length is invariant, and so a length can be measured in different units, and we can convert between those units using multiplication and division (by powers of ten, in the case of the metric system).

Skills students will use:

- multiplication of decimals (e.g., Grade 5, Unit 10)
- division of decimals (e.g., Grade 5, Unit 10)

Students engage in Mathematical Practice 6 (Attend to precision) as they multiply and divide decimal metric measurements to convert all measurements to the same unit, and as they multiply money to determine the best buy.

**Key vocabulary: **

- equivalent
- length
- measurement
- metric abbreviations (km, hm, dam, m, dm, cm, mm)
- metric prefixes (kilo-, hecto-, deka-, deci-, centi-, milli-)