Learning Objectives
- Read time on a clock to the exact minute
- Understand 12-hour and simple 24-hour time
- Calculate time duration (how long something takes)
- Solve word problems related to time and schedules
Key Concepts
Reading Time to the Minute
Each small mark on a clock face stands for 1 minute. There are 60 minutes in one hour. The minute hand moves from one big number to the next in 5 minutes. So when the minute hand is on 3, it is 15 minutes past the hour. When it is on 9, it is 45 minutes past the hour. Practice reading the exact minutes on a clock.
Hours, Minutes, and Seconds
1 hour = 60 minutes. 1 minute = 60 seconds. Half an hour = 30 minutes. Quarter of an hour = 15 minutes. Three quarters of an hour = 45 minutes. A day has 24 hours. Knowing these facts helps you solve time problems quickly.
Calculating Duration
To find how long something takes, subtract the start time from the end time. If a class starts at 10:15 and ends at 11:00, the duration is 45 minutes. If a movie starts at 3:30 p.m. and lasts 2 hours, it ends at 5:30 p.m. Add the duration to the start time to find the end time.
Daily Schedule
A schedule shows the time for different activities during the day. For example: wake up at 6:30 a.m., school starts at 8:00 a.m., lunch at 12:30 p.m., school ends at 2:00 p.m. By looking at a schedule, you can plan your day and know how much time you have for each activity.
Important Terms
- Hour: A unit of time equal to 60 minutes
- Minute: A unit of time equal to 60 seconds
- Second: The smallest common unit of time
- Duration: The length of time something takes from start to finish
- Schedule: A plan showing the times for different activities
- Quarter Past: 15 minutes after the hour
- Half Past: 30 minutes after the hour
Quick Revision
- 1 hour = 60 minutes, 1 minute = 60 seconds
- Each small mark on a clock = 1 minute
- Duration = End time - Start time
- End time = Start time + Duration
- Quarter hour = 15 min, Half hour = 30 min
- A day has 24 hours: 12 hours a.m. + 12 hours p.m.