Page 157 - ICSE Math 4

Time and ime and
T

12
T
Temperatureemperature

Learning Outcomes

Students will be able to learn:
 reading and writing clock time in hours and minutes.
 clock time in a.m. and p.m.

 the relation between 24-hour clock time and 12-hour clock time.
 the conversion of days, hours and minutes (bigger to smaller units and vice versa).
 how to calculate elapsed time by using forward or backward counting/addition and
subtraction.
 measurement of temperature.

We have already learnt in the previous class that clocks and watches are used to read and

tell me. A clock face has markings with numbers from 1 to 12 which denote the hours.
The smaller marking between any two hour markings denote the minutes.

 An hour hand takes 12 hours to complete one round.

 A minute hand takes 1 hour, i.e., 60 minutes to complete one round.

 A second hand takes 1 minute, i.e., 60 seconds to complete one round.

Time in Hours, Minutes and Seconds

We know that me is measured in units of hours, minutes and seconds. The short form of
hours, minutes and seconds are h, min and s, respec vely.

1 day = 24 hours 1 hour = 60 minutes 1 minute = 60 seconds

To read and tell me, we divide the clock into two halves
as shown by the do ed line. 12
11 1
 When the minute hand is on the right side of the 10 2
do ed line, we read the me as number of minutes Quarter Quarter
past a given hour. 9 To Past 3
8 4
 When the minute hand is on the le side of the Half Past
7 5
do ed line, we read the me as number of minutes 6

to the next hour.

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