Lesson objective: Extend understanding about telling time to telling time to the nearest minute.

Students bring prior knowledge of telling time to the nearest five minutes from Grade 2, Unit 4, 2.MD.C.7. This prior knowledge is extended to telling time to the nearest minute as students show their methods for finding time on the number line. A conceptual challenge students may encounter is using efficient methods for showing the time on the number line or clock face.

The concept is developed through work with a number line consisting of sixty minute tick marks for each hour, which extends the students' experiences with using the number line to show time by counting fives. The number line helps students apply what they know about decomposing numbers into more compatible numbers to telling time such as 15, 30, 45, etc.

This work helps students deepen their understanding of numbers because they recognize that numbers represent the number of minute and hour units when measuring time. Also, students connect their experiences with decomposing numbers to telling time. In addition, students develop their understanding of equivalence because they recognize that sixty minutes is equivalent to one hour.

Students engage in Mathematical Practice 5 (use appropriate tools strategically) as they tell time on the analog clock and show their method on the number line. In addition, students engage in Mathematical Practice 4 (model with mathematics) as they use number equations to show their methods for using the number line to find the time.

**Key vocabulary:**

- conventions for writing time - 10:13
- minutes before and after the number of hours when telling time
- number line

**Special materials needed:**

- clocks for each student
- Judy clock for demonstration
- number line with sixty minute tick marks for demonstration