6.1  24-Hour System

 Recognize the 24-hour system

  • The time in the 24-hour system is written using 4 digits.
  • The first 2 digits represent hours and the last 2 digits represent minutes.
  • Example is as below :


 The relationship between the 24-hour system and the 12-hour system

  •  In the 24-hour system, the time in a day is stated from 0000 hours until 2359 hours.
  • Four digits are used in this system.
  • The first two digits represent hours in a day and the last two digits represent minutes.This system avoids confusion of the same time.
  • 12-hour system is differentiated by writing a.m. or p.m.
  • a.m. is ante meridian refers to the time after midnight until before midday.
  • p.m. is post meridian refers to the time after midday until before midnight.
  • For the time in 12-hour system for 1.00 pm untill 11.59 pm, it needs to be added by 12 hours to convert it to 24-hour system.
  • Where as for the a.m. time, there will be no need for addition of 12 hours.
  • Example is as below :

 0800 hours will be stated as below in the 12-hour system :


 Situation 1

 My mother fetches my younger sister from school at 1245 hours. What is the time in the 12-hour system?

                 jam 1245 = 12.45 pm


6.2  Duration

 Units of time

  • Use a clock face.
  • The time ends at the time of arrival.

 Situation 1

 Sumitha and her father board a bus in Tanjung Malim, Perak at 0930 hours. They are expected to arrive at Batang Kali, Selangor at 1015 hours. How long is their journey?


 Situation 2

 Puan Marlia attended a course from 4 March 2016 until 5 May 2016. How long did she attend the course? State the duration in:

 a) days

 b) months and days


 World time zones.

  • Make sure the country’s location is either on the west or east.
  • Find the time difference.
  • Determine the operation.
  • If the country is located in the:
  • If the country is located in the east, add the time difference to the time in the country.
  • If the country is located in the west, subtract the time difference from the time in the country.

 Situation 1


 Question 1

 According to the diagram above, what is the time in Kuala Lumpur if the time in London is 3.00 p.m. ?

  •  Kuala Lumpur is in the east. The time difference is 8 hours.
  • Therefore, add 8 hours to the time in London.
  • The time in Kuala Lumpur = 3:00 p.m. + 8 hours
  •                                           = 1500 hours + 0800 hours
  •                                           = 2300 hours
  •  The time in Kuala Lumpur is 2300 hours or 11:00 p.m..


 Question 2

 According to the same diagram above, state the date and time in Kuala Lumpur if the time in Osaka is 0030 hours on 31 March 2017.

  • Malaysia is located to the west of Osaka.
  • The time difference is 1 hour.
  • Therefore, subtract 1 hour from the time in Osaka.
  • The time in Malaysia is 2330 hours or 11:30 p.m. on 30 March 2017.


6.3  Solve the Problems

 Situation 1

 Suresh was born on 21 March 1988. The age difference between his brother’s and his is 9 years 8 months and 9 days. When is his brother’s date of birth?


 Situation 2 

 Puan Jamilah and her child want to watch a movie. They need to return home at 3:00 p.m.. State the movie and the show time that is suitable for them to watch.