What is a 24-Hour Clock?

The 24-hour clock is a way of telling time that uses numbers from 0 to 23. Instead of starting at 1 in the morning like the 12-hour clock (AM), it starts at 0. This means that when it reaches 12 noon, it continues to count up to 23 before going back to 0 at midnight.

Why Use a 24-Hour Clock?

The 24-hour clock is often used in timetables, train schedules, and in the military. It helps avoid confusion between AM (morning) and PM (afternoon/evening).

Key Rules of the 24-Hour Clock

  1. Midnight is 00:00: The day starts at midnight, which is written as 00:00.
  2. 12 Noon is 12:00: The middle of the day is 12:00.
  3. Times After 12 PM: To convert an afternoon time to the 24-hour clock, add 12 to the hour.
    • For example:
      • 1 PM = 13:00 (1 + 12)
      • 2 PM = 14:00 (2 + 12)
  4. Times Before Noon: Times from midnight to 11:59 AM stay the same.
    • For example:
      • 8 AM = 08:00
      • 10 AM = 10:00
  5. Minutes: The minutes stay the same in both clocks.

Examples

  • 12:30 PM in 24-hour clock is 12:30.
  • 3:45 PM in 24-hour clock is 15:45 (3 + 12).
  • 9:00 AM in 24-hour clock is 09:00.
  • 11:15 PM in 24-hour clock is 23:15 (11 + 12).

Tips and Tricks

  • Remember to add 12: For PM times after 12:00, just add 12 to the hour number.
  • Use a number line: Visualising a number line from 0 to 23 can help you see the hours clearly.
  • Practice by converting: Take a few AM and PM times and convert them to the 24-hour format. This will help you get the hang of it!

Questions on the 24-Hour Clock

Easy Level Questions

  1. What is 00:00 in the 12-hour clock?
  2. What time is 10:00 in the 12-hour clock?
  3. Convert 12:00 PM to the 24-hour clock.
  4. What is 15:00 in the 12-hour clock?
  5. What time is 06:30 in the 12-hour clock?
  6. Convert 11:00 AM to the 24-hour clock.
  7. What is 18:15 in the 12-hour clock?
  8. What time is 01:30 in the 12-hour clock?
  9. What is 23:59 in the 12-hour clock?
  10. Convert 03:00 PM to the 24-hour clock.

Medium Level Questions

  1. What is 22:00 in the 12-hour clock?
  2. Convert 09:45 to the 12-hour clock.
  3. What time is 17:30 in the 12-hour clock?
  4. What is 14:15 in the 12-hour clock?
  5. If it is 20:10, what time is it in the 12-hour clock?
  6. Convert 10:05 PM to the 24-hour clock.
  7. What time is 12:30 AM in the 24-hour clock?
  8. Convert 04:25 to the 12-hour clock.
  9. What is 19:45 in the 12-hour clock?
  10. If it is 11:30 PM, what time is it in the 24-hour clock?

Hard Level Questions

  1. If a train leaves at 16:20, what time is that in the 12-hour clock?
  2. Convert 23:00 to the 12-hour clock.
  3. What is 10:10 AM in the 24-hour clock?
  4. If a movie starts at 19:50, what time is that in the 12-hour clock?
  5. Convert 12:15 AM to the 24-hour clock.
  6. What is 21:30 in the 12-hour clock?
  7. If it is 08:05 PM, what time is it in the 24-hour clock?
  8. Convert 15:15 to the 12-hour clock.
  9. What is 13:00 in the 12-hour clock?
  10. If a flight departs at 22:45, what time is that in the 12-hour clock?

Answers and Explanations

Easy Level Answers

  1. 12:00 AM
  2. 10:00 AM
  3. 12:00
  4. 3:00 PM
  5. 6:30 AM
  6. 11:00
  7. 6:15 PM
  8. 1:30 AM
  9. 11:59 PM
  10. 15:00

Medium Level Answers

  1. 10:00 PM
  2. 9:45 AM
  3. 5:30 PM
  4. 2:15 PM
  5. 8:10 PM
  6. 22:05
  7. 00:30
  8. 4:25 AM
  9. 7:45 PM
  10. 23:30

Hard Level Answers

  1. 4:20 PM
  2. 11:00 PM
  3. 10:10
  4. 7:50 PM
  5. 00:15
  6. 9:30 PM
  7. 20:05
  8. 3:15 PM
  9. 1:00 PM
  10. 10:45 PM

Feel free to practice these questions and get comfortable with the 24-hour clock! Happy learning!