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SAI International School
Sub – Mathematics
Class - IV
Topic – TIME
Sub topic – 12 hours and 24 hours format
Read the following sentences.
It is 6 o’ clock. Anil has just woken up. That means it is morning time.
It is 6 o’ clock. Anil is playing. That means it is evening time.
Similarly, the sentence, “It is 12 o’clock” may mean
It is 12 noon or
It is 12 midnight.
Time from 12 midnight to 12 noon is denoted by a.m. (ante meridian).
So, 6 a.m. refers to 6 o’ clock in the morning.
Time from 12 noon to 12 midnight is denoted by p.m. (post meridian).
So, 6 p.m. refers to 6 o’ clock in the evening.
A day begins at 12 midnight and ends at 12 midnight on the following day. This is called the
12-hour clock.
Example 1: Write the time using a.m. or p.m.
a) 7: 15 in the morning = 7:15 a.m.
b) 9:45 at night = 9:45 p.m.
Example 2: What time will it be:
a) 5 hours after 8 a.m.? b) 45 minutes after 12 noon?
Answer: 2 hours after 8 a.m. is 10 a.m. Answer: 45 minutes after 12 noon
is 12:45 p.m.
2 hours after 10 a.m. is 12 noon.
1 hour after 12 noon is 1 p.m.
Therefore, 5 hours after 8 am will be 1 p.m.
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