Week 7 · Clocks in five-minute steps and division · 3 lessons
1
Reading minutes on the clock
Discover Mathematics P3: Term 1, Lessons 21–30
GoalRead the time to 5 minutes on an analogue clock, write it as digital time and find a later time.
New words
hour hand · the short hand; it shows the hourminute hand · the long hand; it shows the minutesdigital time · time written with numbers, such as 4:35
Explanation
The short hand of a clock is the hour hand and the long hand is the minute hand. When the minute hand points to a number, count by 5s: 1 is 5 minutes, 2 is 10, 3 is 15, 4 is 20, 5 is 25, 6 is 30, and so on, up to 12, which is 0 minutes. To read the time, first look at the hour hand to see which hour it has passed. Then count the minutes by 5s. This clock shows 4:35: the hour hand is just past 4, and the minute hand points to 7, because 7 × 5 = 35. In digital time we write the hour, a colon and the minutes. To find a later time, add the minutes: 25 minutes after 4:35 is 5:00.
Worked examples
The minute hand points to 3, and 3 × 5 = 15. The hour hand is just past 7. The time is 7:15, or 15 minutes past 7.
The minute hand points to 10, and 10 × 5 = 50. The hour hand is close to 3 but has not reached it, so the hour is still 2. The time is 2:50.
The school bus leaves at 7:40 and the trip takes 20 minutes. From 7:40, 20 minutes later is 8:00. The bus arrives at 8:00.
Class activity
Clock hunt. Make a paper clock with hands that move. A grown-up says digital times, such as 3:20, 6:45 and 9:05, and the child sets the hands. Then swap: the child reads three times from a real clock during the day, such as breakfast, school and dinner, and writes each in digital form.
Practice
1
What time does the clock show?
9:25.
2
Write the time in digital form.
1:10.
3
The minute hand points to 8. How many minutes past the hour is that?
40 minutes, because 8 × 5 = 40.
4
A clock shows 5:55 in digital form. Where does the minute hand point?
To 11, because 11 × 5 = 55.
5
Hana’s lesson starts at 10:20 and lasts 30 minutes. When does it end?
