The 24-Hour Clock and Train Timetables: Class 4 Study Guide
Railways and airlines use the 24-hour clock so that morning and evening times cannot be confused.
On the 12-hour clock we use a.m. for the morning and p.m. for the afternoon and night. On the 24-hour clock the hours run from 00:00 (midnight) to 23:59, so there is no a.m. or p.m. Railway tickets in India show times this way.
To change a p.m. time to 24-hour time, add 12 to the hour: 3:30 p.m. is 15:30. A.m. times stay the same, but 12:00 midnight is 00:00 and 12:00 noon is 12:00.
Converting time
| 12-hour time | 24-hour time |
|---|---|
| 6:15 a.m. | 06:15 |
| 12:00 noon | 12:00 |
| 3:30 p.m. | 15:30 |
| 9:45 p.m. | 21:45 |
| 12:00 midnight | 00:00 |
How long is the journey?
This is an example timetable, not a real train. A train leaves at 08:40 and arrives at 14:25. From 08:40 to 09:00 is 20 minutes. From 09:00 to 14:00 is 5 hours. From 14:00 to 14:25 is 25 minutes. The journey takes 5 hours 45 minutes.
08:40 to 09:00 is 20 min.
09:00 to 14:00 is 5 h.
14:00 to 14:25 is 25 min.
5 h 45 min.
Trains that arrive the next day
If a train leaves at 21:30 and arrives at 06:10 the next day, count to midnight first: 21:30 to 24:00 is 2 h 30 min. Then from 00:00 to 06:10 is 6 h 10 min. In all it takes 8 h 40 min.
Worked examples and common mistakes
Example: 7:20 p.m. is 19:20. Example: 18:05 is 6:05 p.m. Common mistakes: writing 24:30 instead of 00:30, subtracting hours and minutes separately without regrouping, and forgetting that 60 minutes make an hour. Use the number line from hour to hour.
Check your understanding: model answers
1. 20:50. 2. 5:30 a.m. 3. 3 hours 25 minutes.
✨ Key Takeaways
- The 24-hour clock has no a.m. or p.m.
- For p.m. times add 12 to the hour.
- Midnight is 00:00.
- Count to the next hour, then the hours, then the minutes.
💬 Questions for Discussion & Reflection
- Write 8:50 p.m. in 24-hour time.
- Write 05:30 as a.m. or p.m.
- A bus leaves at 10:15 and arrives at 13:40. How long is the journey?