Lesson objective: Understand that larger units of time can be converted to smaller units of time using multiplication.

Students bring prior knowledge of units of time from 2.MD.C.7. This prior knowledge is extended to conversions of time as students convert hours to minutes and minutes to seconds. A conceptual challenge students may encounter is understanding that the larger the unit, the fewer units needed.

The concept is developed through work with a function table, which shows the multiplicative relationship between a larger unit of time and a smaller unit of time.

This work helps students deepen their understanding of operations because students learn to use the model to show how many times larger one unit is than another unit.

Students engage in Mathematical Practice 7 (look for and make use of structure) and Mathematical Practice 8 (look for patterns) as they create function tables and look for relationships and patterns within them.

**Key vocabulary:**

- customary unit
- function table
- hour
- minute
- second