Seconds, the 24-hour clock and timetables · Usually met around P3
When it starts and ends
Hours first, then minutes; 60 minutes make an hour.
How to do it
Method
Hours first, then minutes; 60 minutes make an hour
9:40 → 10:40 → 11:15
Another way
Hop along a time line
9:40 → 10:00 → 11:00 → 11:15
In full
Start time, time taken, end time: know two and you can find the third. For the end time, count on from the start: hours first, then minutes, and 60 minutes make 1 more hour. Starting at 9:40 a.m. and taking 1 hour 35 minutes: 9:40 → 10:40, then 35 more minutes, 40 + 35 = 75, and 75 minutes is 1 hour 15 → 11:15. For the start time, count back from the end. For the time taken, count to the next o'clock first, then the rest. Or hop along a time line in chunks.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
An activity starts at 9:40 a.m. and lasts 1 hour 10 minutes. When does it end?
- A. 9:50 a.m.
- B. 11:50 a.m.
- C. 10:50 a.m.
- D. 8:30 a.m.
Choose the right answer
Show the answer and working
Answer: C. 10:50 a.m.
Add the hour, then the minutes, carrying 60 minutes as an hour: 10:50 a.m..
Example 2
How many minutes is it from 9:35 a.m. to 10:05 a.m.?
Show the answer and working
Answer: 30 minutes
To the next o'clock: 25 minutes; then 5 more: 25 + 5 = 30.
Example 3
An activity starts at 9:50 a.m. and lasts 1 hour 20 minutes. It ends at □:□ a.m. (hour, then minutes).
Fill in each box
Show the answer and working
Answer: 11，10
Count on 1 hour 20 minutes from 9:50 a.m.: 11:10 a.m..
Practise it in the game →Seconds, the 24-hour clock and timetables · Free to start, unlimited questions, no download