Measurement / Mensuration - Measuring time: ante meridiem (A.M.) and post meridiem (P.M.)
Introduction
Time measurement is the process of tracking duration using units like hours, minutes, and seconds.
Explanation Step by Step
We use a 12-hour clock system twice a day to complete 24 hours.
Sub-topics
Telling Time
Examples
Example 1: Exactly 9 o'clock
🕘
The small hand is at 9 and the big hand is at 12.
Time: 9:00
Example 2: Half past four
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"Half past" means 30 minutes have passed.
Time: 4:30
Tricks and Shortcuts
To convert minutes to seconds, multiply by 60. To convert seconds to minutes, divide by 60.
Common Mistakes
Confusing 12:00 AM (Midnight) with 12:00 PM (Noon).
Practice Questions
Easy Questions
- How many minutes are in 1 hour?
- What is 15 minutes called? (Quarter/Half)
- How many seconds are in 1 minute?
Medium Questions
- Convert 5 hours into minutes.
- If a movie is 120 minutes long, how many hours is that?
- Is 11:00 in the morning A.M. or P.M.?
Hard Questions
- Calculate the total minutes in 3 hours and 45 minutes.
- Convert 7200 seconds into hours.
- Find the time duration between 11:30 A.M. and 2:15 P.M.
Revision Summary
Remember the 60-60-24 rule: 60 sec = 1 min, 60 min = 1 hr, 24 hr = 1 day.
A movie started at 4:35 PM. The duration of the movie is 2 hours 50 minutes. When will the movie end?
A
7:25 PM
B
7:15 PM
C
7:30 PM
D
7:20 PM
Started studying at 8:05 AM. Studied for 2 hours and 50 minutes. At what time did the study end?
A
10:55 AM
B
11:00 AM
C
10:50 AM
D
11:05 AM