Level 2 · Ages 8–11
Read it again any time, including while you work through the exercises.
Time is not measured with a ruler, but with a clock! Its units are the hour (h), the minute (min) and the second (s). Remember the two key equalities: 1 hour = 60 minutes and 1 minute = 60 seconds.
Careful, time does not count like everyday numbers! With hours, we do not go up to 100: after 60 minutes, hop, a new hour begins. That is why 1 h 30 min is not 130 minutes, but 60 + 30 = 90 minutes.
A duration is the time that passes between a start and an end. If the film starts at 2:00 pm (14 h) and ends at 3:30 pm (15 h 30), its duration is 1 h 30 min.
To compute a duration, the jumping method is your best friend: first jump to the next whole hour, then keep going. From 9:40 to 10:15? A 20 min jump to 10:00, then 15 more minutes: 35 minutes in total.
With a bit of practice, you will be able to say how long break time, the trip or your favourite cartoon lasts, without ever getting it wrong!
The swimming lesson starts at 9:40 and ends at 10:15. How long does it last?
9 h 40 → 10 h : 20 min
First jump: from 9:40 to the whole hour, 10:00. From 40 to 60 there are 20 minutes.
10 h → 10 h 15 : 15 min
Second jump: from 10:00 to 10:15, that is 15 minutes.
20 + 15 = 35
I add the two jumps: 20 + 15 = 35 minutes.
Result: The lesson lasts 35 minutes.