Lesson objective: Extend understanding that skip counting by fives and tens supports telling and writing time to the nearest 5 minutes.

Students bring prior knowledge of telling time from 1.MD.B.3. This prior knowledge is extended to telling time to the nearest five minutes as students investigate how skip counting helps us determine the number of minutes in an hour. A conceptual challenge students may encounter is interpreting the “hour” value when the minute hand is between two numerals on the clock. For example, students may interpret 4:30 as 5:30 because the hour hand is halfway between the 4 and 5 on the face of the clock.

The concept is developed through work with an analog and digital clock, which assist students in making connections between the numerals on a clock and skip counting by five.

This work helps students deepen their understanding of equivalence because we understand that each number on the clock represents the hour and minutes. For example, if the hour hand is on the 5, it’s 5:00. If the minute hand is on 5, it is 25 minutes.

Students engage in Mathematical Practice 6 (Attend to precision) as students precisely communicate their understanding by using appropriate vocabulary terms such as specifying A.M., P.M., analog, and digital.

**Key vocabulary:**

- analog clock
- A.M.
- digital clock
- hour hand
- minute hand
- P.M.

**Special materials needed: **

- geared clocks
- copies of analog and digital clocks