# Video: Applying Operations on Time Using a Digital Clock

Determine the elapsed time from 07:52 am to 06:47 pm.

03:51

### Video Transcript

Determine the elapsed time from 7:52 am to 6:47 pm.

Our starting point is 7:52 am, 7:52 in the morning. And our ending point is 6:47 pm, to 6:47 in the evening. To find the elapsed time, we can break the time down into pieces that are easier to calculate.

We’ll start by calculating how much time has elapsed between 7:52 am and 8:00 am. We know that there are 60 minutes per hour. We started at 52 minutes after 7:00. If we subtract 52 from 60, it will tell us the elapsed time. Eight minutes passed between 7:52 am and 8:00 am.

From this point, let’s calculate elapsed hours instead of elapsed minutes. When one hour passes from 8:00 am, it’s 9:00 am. If another hour passes from 9:00 am it becomes 10:00 am, 10 in the morning. And another hour would make it 11:00 am. Another and it becomes 12:00.

But there’s an important shift here. We’ve now moved over into the noontime. And that means one hour after 11:00 am is 12:00 pm. We add another hour and it’s one o’clock in the afternoon. It’s 1:00 pm. Another hour and it becomes 2:00 pm. Another hour and it’s 3:00 pm. Another hour becomes 4:00 pm, another hour 5:00 pm. One more hour and now it’s 6:00 pm.

Now we need to think about how much time elapses between 6:00 pm and 6:47 pm. Another way to say 6:47 pm is to say 47 minutes after 6:00. And that helps us see that 47 minutes have passed between 6:00 and 6:47.

To find the total elapsed time, we’ll need to add these values up. We can’t add hours and minutes. So we need to add all the hours together and then all the minutes together. If we add up all the one hours, there are 10 of them. There are 10 ones. 10 hours had passed.

Now we add eight minutes and 47 minutes. Eight plus seven is 15. Write the five, carry the one. One plus four is five. Eight plus 47 equals 55, for 55 minutes. When we put those two values together, we get 10 hours and 55 minutes. The total elapsed time from 7:52 am to 6:47 pm is 10 hours and 55 minutes.