Mathematics
Grade 3
15 min
Elapsed time II
Elapsed time II
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Calculate the elapsed time in hours and minutes for a given start and end time.
Determine the end time when given a start time and a duration.
Determine the start time when given an end time and a duration.
Solve one-step word problems involving elapsed time using a number line.
Solve one-step word problems involving elapsed time using a T-chart.
Correctly identify the change from A.M. to P.M. when calculating time that crosses 12:00 noon.
If you put a pizza in the oven at 5:40 P.M. and it needs to bake for 25 minutes, how will you know when to take it out? 🍕 Let's become time detectives!
In this lesson, we will learn how to find a start time, an end time, or figure out how much time has passed between two events. This is a very important skill for...
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Key Concepts & Vocabulary
TermDefinitionExample
Elapsed TimeThe amount of time that passes from the beginning of an event to the end of an event. It's the 'time in between'.The elapsed time from 3:00 PM to 3:45 PM is 45 minutes.
Start TimeThe time when an event or activity begins.Your piano lesson has a start time of 4:30 P.M.
End TimeThe time when an event or activity finishes.School has an end time of 3:15 P.M.
DurationHow long an event or activity lasts. This is another word for elapsed time.A soccer game has a duration of 90 minutes.
Time Number LineA visual tool, like a ruler for time, that helps us 'jump' forward or backward in hours and minutes to find an unknown time.To find the time 20 minutes after 1:10, you can start at 1:10 on a number line and make two jumps of 10 minutes to l...
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Core Formulas
Finding the End Time
Start Time + Duration = End Time
Use this formula when you know when an activity started and how long it lasted. You add the duration to the start time to find when it will be over.
Finding the Start Time
End Time - Duration = Start Time
Use this formula when you know when an activity finished and how long it was. You subtract the duration from the end time to find when it must have begun.
Finding the Duration
End Time - Start Time = Duration
Use this formula when you know the start and end times. You find the difference between them to see how much time passed.
4 more steps in this tutorial
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Challenging
A baking project has two steps. The cookies need to bake for 25 minutes, and then cool for 45 minutes. If you put the cookies in the oven at 4:50 P.M., what time will they be ready to eat?
A.5:50 P.M.
B.6:00 P.M.
C.6:10 P.M.
D.5:15 P.M.
Challenging
A train was scheduled to arrive at 6:00 P.M. but was delayed by 35 minutes. If the train ride was 2 hours and 10 minutes long, what time did the train actually depart?
A.3:50 P.M.
B.4:25 P.M.
C.3:40 P.M.
D.4:00 P.M.
Challenging
A student needs to find the start time for an event that ended at 3:15 P.M. and lasted 45 minutes. They correctly calculate the start time is 2:30 P.M. Which of these number line strategies shows the correct way to work backwards?
A.Start at 3:15, jump back 45 minutes to get 2:30.
B.Start at 3:15, jump back 15 minutes to 3:00, then jump back 30 more minutes to 2:30.
C.Start at 3:15, jump forward 15 minutes to 3:30, then jump forward 30 more minutes to 4:00.
D.Start at 3:00, jump back 30 minutes to 2:30.
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