Math Background

Lesson: Schedules and Elapsed Time
Developing the Concept

Elapsed time is a concept that is best learned by hands-on experience. Using a clock to show time passing, a calendar to show days passing, or a schedule to show how a day passes, is the best way for children to understand elapsed time.

Materials: Learning Tool 44 in the Learning Tools Folder, children's clocks

Preparation: Write a schedule on the board as follows:

Summer Camp Schedule
      9:00    Arts and Crafts
      9:30    Swimming
      10:30    Hiking
      11:30    Lunch
      12:15    Music
      1:00    Story Time
      2:00    Bus Ride Home

Prerequisite Skills and Concepts: Children should be able to read a schedule, tell time, and read and interpret calendars.

Pass out the blank calendars to your children. Have them label the calendar, starting on the first Monday of March.

Calendar showing the month of March

Circulate to be sure that children's calendars are correct. Then ask some basic questions about the calendar, before you continue on to elapsed time in days.

  • Ask: What day of the week is March 23? (Tuesday)
  • Ask: Suppose you had ball practice on Saturdays. How many practice days do you have this month? (4)
  • Ask: What is the date of the second Thursday in this month? (March 11)
  • Say: Let's use this calendar to answer questions about days and weeks. Today is the 7th. Shannon has a party in 5 days.
  • Ask: What is the date of Shannon's party? (March 12)
  • Ask: On what day of the week is her party? (Friday)
  • Say: Explain how you got the answer.
    Elicit that children counted on 5 days from the 7th. Be sure children understand that they count on beginning with the 8th — 8th, 9th, 10th, 11th, 12th.
  • Say: It was Wednesday the 9th and Sean was waiting for his party invitation. His aunt said the invitations were mailed out a week before.
  • Ask: On what date were the invitations mailed out? (March 2nd)
  • Ask: How did you solve Sean's invitation problem?
    Guide children to explain that they counted back one week-or 7 days to find the date the invitations were mailed out.

    Repeat with several more scenarios, providing increasingly complex situations.

  • Say: Let's put the calendars aside. I want you now to take a look at a schedule I have for a summer camp. This is a schedule for a Thursday. Let's look at the schedule and see what happens at the camp.
  • Ask: What time is lunch? (11:30)
  • Ask: What activity is an hour and a half after lunch? You can use your clock to help you solve this. (Story time)
    Have children explain how they figured out the answer. Lead children to discuss how they used the clock to show 11:30, then showed an hour pass, and then 30 minutes more on their clocks.
  • Ask: Which activity happened three and one half hours before going home?(Hiking)
  • Ask: How did you get your answer?
    Lead children to explain that they started at 2:00, the time of the bus ride home, and then counted back three and a half hours. Remind them to be aware of important words like before and after which tell them whether to count the hours back or forward.

    Repeat with other scenarios.

Wrap-Up and Assessment Hints
You can informally evaluate children's understanding of elapsed time by developing a schedule of class activities for a day. Round times to the nearest hour or half hour. During the day ask questions about elapsed time using the schedule. Ask students to make up a question and take turns providing the answers. If students need additional practice, provide a daily schedule each day and take time to discuss the activities for the day in terms of elapsed time. For example, say, “It's 9:30. We go to the cafeteria for lunch in an hour and a half. John, please tell us what time we need to leave.”

Houghton Mifflin Math Grade 2