74
Calculating with hours and minutes
Textbook: Part 2, lesson 71, pp. 64–65
GoalCalculating with hours and minutes: regrouping 60 minutes.
New words
hour · soatminute · minutbreak · tanaffusbeing late · kechikish
Explanation
When adding, if the minutes reach 60 or more, change 60 minutes into 1 hour: 1 h 50 min + 2 h 40 min = 3 h 90 min = 4 h 30 min. When subtracting, if there are not enough minutes, change 1 hour into 60 minutes: 7 h 20 min − 3 h 50 min = 6 h 80 min − 3 h 50 min = 3 h 30 min.
Worked examples
2 h 15 min + 3 h 45 min = 5 h 60 min = 6 h.
16 h − 13 h 40 min = 15 h 60 min − 13 h 40 min = 2 h 20 min.
Class activity
“Time counters”: a day plan: wake up 7:00, school 8:30, club 15:45. Pairs work out the time between events and say the answer as “… h … min”.
Practice
1
1 h 50 min + 2 h 40 min = ?
4 h 30 min
2
6 h 20 min − 3 h 30 min = ?
2 h 50 min
3
It is 15:45 now. A class starts at 17:20. How much time is there?
1 h 35 min
4
Lola spent 25 minutes tidying up and 37 minutes on the road. How many minutes in total?
62