GoalFind how much time passed between a start time and an end time in hours and minutes.
New words
elapsed time · the amount of time that passes from a start to an endstart time · the time when something beginsend time · the time when something finishes
Explanation
Elapsed time is how long something takes. To find it, jump from the start time to the end time in easy steps. First jump to the next whole hour, then jump by whole hours, then add the last minutes. Finally add all the jumps. From 10:00 a.m. to 3:30 p.m.: 10:00 a.m. to 12:00 noon is 2 hours, 12:00 noon to 3:00 p.m. is 3 hours, and 3:00 to 3:30 p.m. is 30 minutes. The total is 2 hours + 3 hours + 30 minutes = 5 hours 30 minutes. For short times, such as a morning routine from 6:45 a.m. to 7:30 a.m., jump to 7:00 (15 minutes) and then to 7:30 (30 minutes): 15 + 30 = 45 minutes.
Step
What to do
1
Jump from the start to the next whole hour
2
Jump by whole hours
3
Jump the last minutes
4
Add all the jumps
Worked examples
From 10:00 a.m. to 3:30 p.m. there are three jumps: 2 hours, then 3 hours, then 30 minutes. The total is 5 hours 30 minutes.
Hana wakes up at 6:45 a.m. and leaves for school at 7:30 a.m. 6:45 to 7:00 is 15 minutes, and 7:00 to 7:30 is 30 minutes. She takes 15 + 30 = 45 minutes to get ready.
A film starts at the time on the clock, 4:20 p.m., and ends at 6:05 p.m. 4:20 to 5:00 is 40 minutes, 5:00 to 6:00 is 1 hour and 6:00 to 6:05 is 5 minutes. The film lasts 1 hour 45 minutes.
Class activity
Time detective. Write down the time you start and finish three things today, such as lunch, homework and a walk. Use jumps to find how long each took, in hours and minutes. Which took the longest? Then plan a trip that starts at 9:15 a.m. and lasts 4 hours 30 minutes. When does it end?
Practice
1
School starts at 8:00 a.m. and ends at 2:00 p.m. How long is the school day?
8:00 a.m. to 12:00 noon is 4 hours and 12:00 to 2:00 p.m. is 2 hours. The day is 6 hours.
2
A bus trip starts at 9:15 a.m. and ends at 11:45 a.m. How long is the trip?
9:15 to 11:15 is 2 hours and 11:15 to 11:45 is 30 minutes. The trip takes 2 hours 30 minutes.
3
Marwan starts his homework at the time on the clock (p.m.) and finishes at 6:00 p.m. How long does he work?
The clock shows 5:10 p.m. From 5:10 to 6:00 is 50 minutes.
4
A football camp runs from 1:30 p.m. to 4:15 p.m. How long is it?
1:30 to 2:00 is 30 minutes, 2:00 to 4:00 is 2 hours and 4:00 to 4:15 is 15 minutes. The camp lasts 2 hours 45 minutes.
5
Mina wakes up at 6:20 a.m. and leaves at 7:05 a.m. How long does she take to get ready?
6:20 to 7:00 is 40 minutes and 7:00 to 7:05 is 5 minutes. She takes 45 minutes.
