Lesson objective: Understand that metric units can be converted from smaller to greater units by using division with powers of 10.

Students bring prior knowledge of the use of multiplicative comparison to convert between units of length from 4.OA.3. This prior knowledge is extended to the use of division to convert between smaller to greater measurement units as students determine whether 1 meter is equivalent to 1000 km or 0.001 km. A conceptual challenge students may encounter is finding it difficult to divide when making unit conversions because this will frequently involve the use of decimals.

The concept is developed through work with a measurement chart, which is related to the Base Ten Place Value system.

This work helps students deepen their understanding of number because, like the place value system, we multiply or divide by powers of 10 to convert between metric measurement units.

Students engage in Mathematical Practice 2** **(Reason abstractly and quantitatively) as they make sense of how metric measurement units compare, such as 10 mm = 1 cm, 100 cm = 1 m, 1000 m = 1 km. Students will make sense of quantities and their relationships in problem situations by converting between various metric units when measuring length.

**Key vocabulary:**

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