Lesson 12

The purpose of this warm-up is for students to notice that they can use the structure of the analog clock to count by 5. They compare what they know about number lines that label intervals of 5 to the labeled numbers on a clock. This will be useful when students tell time in a later activity. While students may notice and wonder many things about these images, the important discussion points are that the number of minutes are increasing by 5 as they move around the labeled numbers on an analog clock.

• Groups of 2
• Display the image.
• “What do you notice? What do you wonder?”
• 1 minute: quiet think time

• “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Share and record responses.

• “How are these images alike?” (They both show counting by 5.)
• “What is different about the way 0 and 5 are represented?” (The clock shows two zeros and “05” instead of just 5.)
• “The numbers around the clock show how we write minutes on a digital clock. We always use two digits on the minute side of a digital clock even when the number of minutes is less than ten.”
• “Let’s count by 5 together as we look at each image.”
• Point to the numbers on the number line as you count from 0 to 55. Repeat with the numbers on the outside of the clock.

The purpose of this activity is for students to practice counting by 5 in order to tell time on an analog clock. In the launch, students practice using what they notice in the warm-up to tell time to the nearest 5 minutes on an analog clock. Then they work in partners to tell the time on analog clocks and sequence their cards in time order. During the synthesis, students discuss how they use the labeled numbers on the clock to determine the time and discuss what they notice about how the hour hand moves as more time passes in minutes.

• Create a set of cards from the blackline master for each group of 2. 

• Groups of 2
• Display the image of the clock that shows 4:30 with the minutes labeled on the outside.
• “Tell your partner 2 ways to read this time.” (4:30 or half past 4)
• 30 seconds: partner discussion
• “How could you prove that the time is 4:30?” (Each tick mark shows one minute. You could count by 1 to 30. You can count the minutes by 5. Start at the 12 and count by 5 for each number until you get to 6. 5, 10, 15, 20, 25, 30. So it is 4:30.)
• 1 minute: partner discussion
• Share responses.
• Display the image of the clock that shows 4:15.
• “What time does this clock show?” (4:15 or quarter past 4)
• 1 minute: partner discussion
• Share responses.
• “When telling time, we can count by 5 to determine how many minutes have passed since the hour.”
• Use a clock to demonstrate starting at 4:00 and moving the minute hand to the 1, 2, then 3, as you say, “4:00, 4:05, 4:10, 4:15.”
• Give each group a set of cards.

• “You are going to continue counting by 5 to tell time. Take turns telling the time on your cards. Work together to put the cards in order based on the times they show.”
• 8 minutes: partner work time

If students sequence the clocks in any order other than the expected sequence, consider asking:

• “How did you decide where to place each clock?”
• “How can you use the position of the hour hand to tell if your clocks are in the right order?”

• Invite students to share the correct card sequence.
• Display the cards as students name which card would go next.
• As students share, consider asking:
  • “How did you know what hour the clock shows?”
  • “How did you know how many minutes the clock shows?”
• “What do you notice about the hour hand when you look at the clocks in order?” (It moves a little toward the next hour each time. It is getting closer and closer to 9.)

The purpose of this activity is for students to practice telling and writing time using an analog clock. They count by 5 to identify the minutes and pay close attention to the hour hand as it approaches the next hour. Students complete a digital clock to show the time. When students look for shortcuts to tell the time (for example, counting on from 30 rather than 0 or counting back from 60), they are looking for and expressing regularity in repeated reasoning (MP8).

• Groups of 2

• “Now you will tell and write the time shown on an analog clock. Remember to pay close attention to the hour hand as the minute hand gets closer to the 12.”
• “After writing the times, compare with a partner.”
• 3 minutes: independent work time
• 3 minutes: partner work time
• Monitor for a student who counts on from 30 to tell time when the minute hand is past the 6.

If students start counting by 5 at 12 or lose track when starting from a number on the clock other than 1, consider asking:

• “Can you explain how you got ___?”
• “How could you use what you know about half past ___ to count on to find the time?”

• Display the image of the clock that shows 2:40.

  

  

• Invite previously identified students to share their strategy for finding the time.
• “How did _____ know you could start counting at 30? Why does this work?” (They know it is 2:30 when the minute hand points to 6, so they can just start there. It works because you will still count the same numbers. If you start at 30 you still say 35, 40. It is just faster.)
• Display the clock that shows 3:05 and write 3:5, 3:05, 3:50.
• “Which is the correct way to show the time on the clock using digits? Explain.” (3:05 because it’s five minutes after 3. You have to use 2 digits to show the minutes. It can’t be 3:50 because the minute hand would be closer to the 12 and the hour hand would be closer to the 4.)