Page 153 - Mathematics_Std_4

leap year 366 days
short year 365 days

Note that, division is applied when changing a small unit to a

large unit, whereas multiplication is used when changing a large
FOR ONLINE READING ONLY
unit to a small unit.

Example 1

How many minutes are there in 720 seconds?

Solution
1 minute = 60 seconds

720 seconds = 720 minutes
60
= 12 minutes

Therefore, there are 12 minutes in 720 seconds.

Example 2

A pupil takes 15 minutes to walk from home to school.
Convert this time into hours.

Solution
1 hour = 60 seconds

15 minutes = 15 hours
60
Therefore, 15 minutes = 15 hours.
60

Example 3

How many minutes are there in 72 hours?

Solution
1 hour = 60 seconds
×
72 hours =72 60 minutes
= 4320 minutes
Therefore, there are 4320 minutes in 72 hours.

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MATHEMATICS STD 4 PB 2024.indd 146
MATHEMATICS STD 4 PB 2024.indd 146 07/11/2024 14:06:13