Reading 24-hour clock time

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  1. Introduction to Reading 24-Hour Clock Time:
  2. What is 24-hour clock time?
  3. Equivalent 24-hour times on the analog clock
  4. Comparing 12-hour times and 24-hour times in a table
  5. How to convert between 12-hour clock time (AM/PM) and 24-hour clock time
  1. Converting AM/PM Time into 24-Hour Time
    Write as 24-hour time instead of AM/PM time.
    1. 9:56 AM
    2. 6:18 AM
    3. 1:35 PM
    4. 4:27 PM
    5. 12:01 AM
  2. Converting 24-Hour Time into AM/PM Time
    Write as AM/PM time instead of 24-hour time.
    1. 05:40
    2. 22:23
    3. 18:05
    4. 11:37
    5. 00:51
  3. Noon and Midnight are Special Exceptions for 24-Hour Time
    Answer the questions about special times in the day.
    1. How do you write noon and midnight in AM/PM time?
    2. How do you write noon and midnight in 24-hour time?
    3. What is the rule for all other time conversion (not noon or midnight) for AM and PM hours into 24-hour time?
  4. 24-Hour Time - True False Questions
    Read the descriptions of the time shown below. Write true (T) or false (F) for each description.


    Time: Reading 24-Hour Clock Time
    Topic Notes

    In this lesson, we will learn:

    • 24-hour clock time is used instead of 12-hour clock time to avoid being confused about AM or PM
    • There are 24 hours in a day, so instead of the hours being labelled 1-12 AM or 1-12 PM, we can label them from 1-24 instead.
    • There are rules for converting between 12-hour clock time and 24-hour clock time (and vice versa)


    • Using 12-hour clock time can be confusing because you might not know if someone is telling you a time for AM or PM (ex. is it 6 o’clock in the morning or evening?)

    • By using 24-hour clock time, we can avoid the confusion of not knowing AM/PM
      • There are 24 hours in a day
        • The previous days ends, and the new day starts at midnight (12:00 AM)
        • The middle of the day is right at noon (12:00 PM)
      • For 24-hour time, you say the hours directly from 00 until 24 (or back to 00)
    Time: Reading 24-Hour Clock Time

    • This table shows all the equivalent times for the 12-hour clock and 24-hour clock:
    Time: Reading 24-Hour Clock Time

      • When it goes to midnight (12AM), it becomes 24:00 which is the same as 00:00
      • Do not use this table when doing the practice questions; only for checking

    • To convert from AM/PM time (12-hour clock time) to 24-hour time:

    • \qquad 1. Minutes: stay the same
      \qquad 2. Hours:
        • if AM, keep the same (add leading 0)
        • if PM add 12

      \qquad 3. Exceptions: 12AM = 00h, 12PM = 12h
      • Ex. (8:46AM = 08:46), (5:13PM = 17:13), (12:07AM = 00:07)

    • To convert from 24-hour time to AM/PM time :

    • \qquad 4. Minutes: stay the same
      \qquad 5. Hours
        • if < 12, keep same, remove leading 0, and write AM
        • if > 12 subtract 12 and write PM

      \qquad 6. Exceptions: 00:00 = 12AM and 12:00 = 12PM
      • Ex. (09:54 = 9:54AM), (22:38 = 10:38PM), (00:16 = 12:16AM)