# What is Elapsed Time? Rating

Ø 5.0 / 3 ratings
The authors Team Digital
What is Elapsed Time?
CCSS.MATH.CONTENT.3.MD.A.1

## Elapsed Time

Freddie receives a letter from Zuri one day about a scavenger hunt. He needs to follow all of the clues to get a surprise at the end! However, he needs to make sure he gets to all of the clues in time for his surprise. In order to do this Freddie will need to use elapsed time strategies and elapsed time using a number line. Read more below to learn more about how to find elapsed time.

## What is Elapsed Time?

What’s elapsed time? Have you ever wondered “what does elapsed time mean?” Elapsed time or time elapsed is how long an activity takes from beginning to end. In this video we explore how to calculate elapsed time using a number line. We can also find this by measuring elapsed time.

## How to Determine Elapsed Time

To find elapsed time, always begin by putting the start time on the LEFT side of the number line. Next, we can put our end time on the RIGHT side of the number line. Then, skip count, or count forward until you reach the end time. When skip counting with time it can be helpful to skip count by the largest unit of time first.

## Elapsed Time – Examples

Take a look at the elapsed time number line below. It shows the starting time one the right side of the number line. It also has the end time on the left side of the number line. We can calculate elapsed time using skip counting on the number line. If we skip count forward small amounts we find that the time elapsed is forty-five minutes. ## Elapsed Time – Practice

Your turn! Try calculating the number line elapsed time on the problem below. Freddie left his house at 6:45 and got to his friend’s house at 7:20, how much time has elapsed? Remember that elapsed time is how long an event lasts from beginning to end. These are the steps you can take to find how much time has elapsed:

Step # What to do
1 Put the starting time on the left side of the number line.
2 Put the end time on the right side of the number line.
3 Skip count forward small amounts until you reach the end time.
4 The amount you counted is the elapsed time.

The first step is to put the start time on the left side of the number line.

Then put the end time on the right side of the number line.

Next, skip count forward small amounts until you reach the end time.

Well, how much time elapsed from beginning to end?

Thirty-five minutes have elapsed from beginning to end.

## Elapsed Time – Summary

Remember, if you want to find how much time has elapsed, follow these steps to determine elapsed time:

Step # What to do
1 Put the starting time on the left side of the number line.
2 Put the end time on the right side of the number line.
3 Skip count forward small amounts until you reach the end time.
4 The amount you counted is the elapsed time.

After this video, you can find continued practice of elapsed time through elapsed time problems and worksheets.

## What is Elapsed Time? exercise

Would you like to apply the knowledge you’ve learned? You can review and practice it with the tasks for the video What is Elapsed Time?.
• ### Solving the elapsed time.

Hints

Count forward in hours first, then in minutes.

Remember to put the start time on the left side of the number line and the finish time on the right side of the number line.

Solution
• To get from 9:20 to 11:35:
• First, count forward by 1 hour to reach 10:20.
• Then, count forward by another hour to reach 11:20.
• Next, count forward by 10 minutes to reach 11:30.
• Finally, count forward by 5 minutes to reach 11:35.
• ### Arrival time of flights.

Hints

First, count forward from the start time by 1 hour.

Then, count forward by 30 minutes until you reach the end time.

You might need to break 30 minutes into smaller chunks of time, like 10 minutes.

Solution

If we use a number line to count forward by one hour, then by 30 minutes, the departure and arrival times would be:

Depart: 4:20 Arrive: 5:50

Depart: 8:25 Arrive: 9:55

Depart: 4:40 Arrive: 6:10

Depart: 10:05 Arrive: 11:35

• For the flight that leaves at 4:40: Add 1 hour to get to 5:40, then add 30 minutes. We need to think of this as 20 minutes to reach 6:00, then another 10 minutes to reach 6:10. In total, 1 hour and 30 minutes has been added on.
• ### How long was the train ride?

Hints

Remember that there are 60 minutes in an hour, so we would count 1 hour, or 60 minutes, to get to the next hour.

Remember to first count forward in hours, then in minutes.

You can break up the minutes into smaller chunks to add. For example, 30 minutes could be broken into 20 and 10.

Solution
• To get from 4:15 to 6:10.
• First, count forward by 1 hour to reach 5:15.
• Then, count on 45 minutes to reach 6:00.
• Finally, count forward 10 minutes to reach 6:10.
• ### How long does each TV show last?

Hints

Count forward in hours first from the start time. Then add the minutes in smaller chunks.

When drawing a number line to solve the elapsed time, remember to put the start time on the left side and the end time on the right side.

Solution
• This image shows a number line to find the elapsed time of Attack of the Really Big Slugs: Start: 2:35 and End: 4:20 = 1 hr 45 mins
• Talent Show: Start: 7:15 and End: 8:35 = 1 hr 20 mins
• Knights and Dragons: Start: 3:55 and End: 5:20 = 1 hr 25 mins
• Super Bowl: Start: 8:30 and End: 10:25 = 1 hr 55 mins
• ### Finding the elapsed time.

Hints

Remember that the first thing we do, is to put the start time on the left side of the number line.

Remember to start your jumps in hours.

Solution

Put the start time on the left side of the number line and the end time on the right side of the number line.

Start by counting forward in hours.

Then count forward in minutes.

Count up the total time you skip counted.

• ### The soccer game.

Hints

Make sure to add all the times up (the playing, the break, and the injury time) to find how long the game lasted in total.

If we took off the injury time, that means that the game would finish 5 minutes earlier.

Solution
• In addition to the playing time, there was a half-time break and injury time of 20 minutes total added on.
• The whole game finished at 9:20pm.
• If it hadn't been for the injury, they would have finished at 9:15pm.
• Last week they went to a game that had no injury time. The game was 105 minutes long, or 1 hour and 45 minutes.
• It started at 2:40pm and finished at 4:25pm.
• After that game, they went to get the bus home and only had 20 minutes to catch it, as it left at 4:45pm.
• They were on the bus for 1 hour and 20 minutes, so they finally got off the bus at 6:05pm.