8
Review: hours and minutes
Textbook: Part 1, lesson 8, pp. 25–27
GoalReview working with hours and minutes and finding elapsed time.
New words
hour · soatminute · minutclock face · siferblatday (24 hours) · sutka
Explanation
1 hour = 60 minutes and 1 day = 24 hours. We write times as hours:minutes, for example 7:05. To find elapsed time, convert both times to minutes and subtract, or add hours and minutes to the start time.
Worked examples
A lesson starts at 8:30 and ends at 9:15: from 8:30 to 9:00 is 30 minutes, from 9:00 to 9:15 is 15 minutes, 30 + 15 = 45 minutes in all.
2 hours 15 minutes = 2 × 60 + 15 = 135 minutes.
Class activity
“Set the clock”: using paper clocks, children show a time the teacher names (for example 6:50), then show the time 25 minutes later.
Practice
1
How many minutes are in 3 hours?
180
2
A lesson started at 8:30 and ended at 9:15. How many minutes did it last?
45
3
How many minutes is 1 hour 40 minutes?
100
4
A film began at 18:40 and lasted 1 hour 50 minutes. At what time did it end?
20:30
5
Azim woke up at 6:00, exercised for 50 minutes, then got ready for 20 minutes. At what time was he ready?
7:10