12-hour time, 24-hour time and elapsed time

Converting between 12-hour (am/pm) and 24-hour time, calculating elapsed time, and reading timetables.

24-hour time

Count up in friendly jumps: to the next whole hour, then whole hours, then the leftover minutes.

Example 1●●

A movie starts at 6:45 pm and finishes at 9:10 pm. How long is it?

6:45 to 7:00 is $15$ min.

7:00 to 9:00 is $2$ h. 9:00 to 9:10 is $10$ min.

Total: $2$ h $25$ min.

Example 2: timetable●●

A train leaves Parramatta at 08:52 and the trip to Central takes $27$ minutes. When does it arrive?

08:52 plus $8$ min is 09:00. $27 - 8 = 19$ min more.

It arrives at 09:19.

Flashcards

4:15 pm in 24-hour time

16:15

00:30 in 12-hour time

12:30 am

Elapsed time method

Jump to the next hour, then whole hours, then minutes.

Practice

A movie runs from 6:45 pm to 9:10 pm. How long is it in minutes?
A train leaves at 08:52 and takes $27$ min. When does it arrive? (24-hour time, like 09:05)
3:20 pm in 24-hour time is:
21:05 in 12-hour time is:
00:40 is:
How many minutes from 10:30 am to 2:00 pm?
A shift runs from 07:15 to 16:30. How many minutes is it?
A 50-minute lesson ends at 11:10 am. When did it start?