Page 121 - Viva

24-Hour Clock
24-hour clocks are mostly used at places such as railway stations, airports and
hospitals. In a 24-hour clock, the day runs from midnight to midnight and is divided into

24 hours.
• The format of a 24-hour clock is hours : minutes. It can also be written as hours
followed by minutes like 1430 hours where the first two digits represent hours and
the next two digits represent minutes.

• 12 o’clock midnight is written as 00:00 or 0000 hours to begin a day. It is also written
as 24:00 or 2400 hours to mean the end of a day. Thus, 24:00 of a day is the same as

00:00 of the next day.
• We write a zero before numbers less than 10. For example, 06:40 is written as
0640 hours and 01:00 is written as 0100 hours.

• 12 o’clock noon is written as 1200 hours or 12:00.

• In a 24-hour clock, after 1200 hours, we read time in the following way.

1200 hours + 0100 hours = 1300 hours for 1 p.m.

1200 hours + 0200 hours = 1400 hours for 2 p.m.

1200 hours + 0300 hours = 1500 hours for 3 p.m.

1200 hours + 0400 hours = 1600 hours for 4 p.m., and so on.

See the given table to compare 24-hour clock with 12-hour clock.

24-Hour Clock 12-Hour Clock 24-Hour Clock 12-Hour Clock
00:00/0000 hours 12 midnight 13:00/1300 hours 1:00 p.m.

01:00/0100 hours 1:00 a.m. 14:00/1400 hours 2:00 p.m.
02:00/0200 hours 2:00 a.m. 15:00/1500 hours 3:00 p.m.

03:00/0300 hours 3:00 a.m. 16:00/1600 hours 4:00 p.m.
04:00/0400 hours 4:00 a.m. 17:00/1700 hours 5:00 p.m.

05:00/0500 hours 5:00 a.m. 18:00/1800 hours 6:00 p.m.
06:00/0600 hours 6:00 a.m. 19:00/1900 hours 7:00 p.m.

07:00/0700 hours 7:00 a.m. 20:00/2000 hours 8:00 p.m.
08:00/0800 hours 8:00 a.m. 21:00/2100 hours 9:00 p.m.

09:00/0900 hours 9:00 a.m. 22:00/2200 hours 10:00 p.m.
10:00/1000 hours 10:00 a.m. 23:00/2300 hours 11:00 p.m.

11:00/1100 hours 11:00 a.m. 24:00/2400 hours 12 midnight
12:00/1200 hours 12 noon

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