Elapsed time word problems

Key Notes :

Understanding Elapsed Time

  • Elapsed time is the amount of time that passes from the start time to the end time.
  • Example: If you start watching a show at 2:00 PM and it ends at 3:00 PM, the elapsed time is 1 hour.

Time Units to Know

  • Hour = 60 minutes
  • Half hour = 30 minutes
  • Quarter hour = 15 minutes

Reading Time on Clocks

  • Students should be able to read both analog and digital clocks.
  • Practice reading time to the hour and half hour, and gradually to the nearest 5 minutes.

Solving Word Problems

Read the word problem carefully.

Identify:

  • Start time
  • End time

Whether to add or subtract time

Use a number line, a clock, or draw the hands on a clock to find the elapsed time.

Strategies to Solve Elapsed Time Problems

  • Count forward in hours and minutes from the start time.
  • Break down time into parts (e.g., 1 hour + 20 minutes).
  • Use T-charts to keep track of time changes.

Practice Problems Include

  • Finding the end time (start time + elapsed time)
  • Finding the start time (end time − elapsed time)
  • Finding the elapsed time (difference between start and end time)

Use of Visual Aids

  • Number lines and clock faces help visualize the passing of time.
  • Encourage drawing clocks to show time changes step-by-step.

Real-Life Connections

Use daily routines to discuss elapsed time, like:

  • How long a movie lasts
  • Time spent at lunch or recess
  • Duration of a school subject

Learn with an example

✈️ Duncan drove to the mall on a busy shopping day. He got to the mall car park at 6:30 P.M., but he didn’t find a parking spot until 7:00 P.M.

How long did it take Duncan to find a parking spot?

_____hours_____ minutes

  • Find the elapsed time.
  • Start: 6:30 P.M.
    End: 7:00 P.M.
  • Count the minutes from 6:30 P.M. to 7:00 P.M. This is 30 minutes.
  • The elapsed time is 30 minutes.

✈️ Gabe started cleaning his room at 10:00 A.M. He finished cleaning it at 10:30 A.M.

How long did it take Gabe to clean his room?

 ____hours ____ minutes

  • Find the elapsed time.
  • Start: 10:00 A.M.
    End: 10:30 A.M.
  • Count the minutes from 10:00 A.M. to 10:30 A.M. This is 30 minutes.
  • The elapsed time is 30 minutes.

✈️ It was 4:00 P.M. when Ernest began mowing the lawn, and he finished at 4:30 P.M.

How long did it take Ernest to mow the lawn?

____hours ____minutes

  • Find the elapsed time.
  • Start: 4:00 P.M.
    End: 4:30 P.M.
  • Count the minutes from 4:00 P.M. to 4:30 P.M. This is 30 minutes.
  • The elapsed time is 30 minutes.

Let’s practice!🖊️