Lesson objective: Understand that ratios can be used to convert between units of measurement.

Students bring prior knowledge of converting between units using multiplication from 4th Grade (4.MD.A.1). This prior knowledge is extended to using ratio reasoning to convert measurement units as students transform units when multiplying and dividing quantities. A conceptual challenge students may encounter is shifting their thinking from additive relationship between quantities to a multiplicative relationship between quantities.

The concept is developed through work with a ratio table, which helps students visualize the relationship between the quantities.

This work helps students deepen their understanding of equivalence as they explore the relationship between quantities that are the same but have different units.

Students engage in Mathematical Practice MP4: (model with mathematics) as they use tables, number lines and diagrams in order to explain their thinking. Students are presented with a real-life situation and will choose which mathematical tools they will use in order to represent their thinking.

**Key vocabulary:**

- conversion
- double number line
- multiplicative relationship