24-Hour Clock Worksheet for 10-Year-Olds — Math Time Practice

Instructions

Read the quick guide below to understand the 24-hour clock, a system used worldwide to avoid confusion between a.m. and p.m. Then, work through the activities to become a master of time!

A Quick Guide to the 24-Hour Clock

The 24-hour clock is simple! Instead of the clock resetting after 12 o'clock, it keeps counting all the way to 23:59.

• The day starts at 00:00 (midnight).
• Times in the morning (a.m.) look similar. For example, 7:30 a.m. is written as 07:30.
• For times in the afternoon and evening (p.m.), just add 12 to the hour. For example, 3:00 p.m. becomes 15:00 (because 3 + 12 = 15).
• The only p.m. hour you don't add 12 to is the 12 p.m. hour. 12:45 p.m. (lunchtime) is simply 12:45.

Part 1: Convert to 24-Hour Time

Change these 12-hour times into 24-hour times. The first one is done for you!

Example: 4:00 p.m. = 16:00

1. 2:30 p.m. = _______________
2. 8:00 a.m. = _______________
3. 10:15 p.m. = _______________
4. 11:50 a.m. = _______________
5. 6:00 p.m. = _______________
6. 12:25 a.m. (just after midnight) = _______________
7. 1:45 p.m. = _______________
8. 12:00 p.m. (noon) = _______________

Part 2: Convert to 12-Hour Time

Now go the other way! Change these 24-hour times back into 12-hour times. Remember to include a.m. or p.m.

Example: 19:00 = 7:00 p.m.

1. 15:00 = _______________
2. 09:30 = _______________
3. 23:10 = _______________
4. 13:45 = _______________
5. 00:55 = _______________
6. 12:10 = _______________
7. 18:20 = _______________
8. 05:00 = _______________

Part 3: Time Traveler's Puzzles

Read the questions below and write your answer.

1. Your family has dinner reservations at 19:00. Is this an early breakfast or a late dinner? What time is it in the 12-hour format?
   ____________________________________________________


2. You want to watch a movie that starts at 14:30. Your friend asks you to play outside at 2:00 p.m. Can you do both? Explain why or why not.
   ____________________________________________________
   ____________________________________________________


3. Your train is scheduled to depart at 08:00. The journey is 3 hours and 30 minutes long. What time will you arrive at your destination in 24-hour format?
   ____________________________________________________

Answer Key

Part 1: Convert to 24-Hour Time

1. 2:30 p.m. = 14:30
2. 8:00 a.m. = 08:00
3. 10:15 p.m. = 22:15
4. 11:50 a.m. = 11:50
5. 6:00 p.m. = 18:00
6. 12:25 a.m. (just after midnight) = 00:25
7. 1:45 p.m. = 13:45
8. 12:00 p.m. (noon) = 12:00

Part 2: Convert to 12-Hour Time

1. 15:00 = 3:00 p.m.
2. 09:30 = 9:30 a.m.
3. 23:10 = 11:10 p.m.
4. 13:45 = 1:45 p.m.
5. 00:55 = 12:55 a.m.
6. 12:10 = 12:10 p.m.
7. 18:20 = 6:20 p.m.
8. 05:00 = 5:00 a.m.

Part 3: Time Traveler's Puzzles

1. It is a late dinner. The time is 7:00 p.m.
2. No, you can't do both. 14:30 is 2:30 p.m., so you would still be playing with your friend when the movie starts. (Or a similar explanation).
3. You will arrive at 11:30.