time · Year 5 · AC9M5M03
24-hour time and am/pm
In 12-hour time the day is split in two: am is from midnight to midday, and pm is from midday to midnight. In 24-hour time the hours keep counting after midday: 1 pm is 13:00, 2 pm is 14:00. So for a pm time, add 12 to the hour to get 24-hour time, and take 12 away to go back. Two hours are special. The hour after midnight is 12 am, written 00 in 24-hour time. The hour after midday is 12 pm, which stays as 12. 24-hour times never use am or pm.
Sample questions
Write 18:10 in 12-hour time, using am or pm.
- 18:10 is after 12:00 midday, so it is a pm time.
- Take 12 away from the hour: 18 − 12 = 6.
- 18:10 is 6:10 pm.
Answer: 6:10 pm
Write 13:35 in 12-hour time, using am or pm.
- 13:35 is after 12:00 midday, so it is a pm time.
- Take 12 away from the hour: 13 − 12 = 1.
- 13:35 is 1:35 pm.
Answer: 1:35 pm
Write 15:30 in 12-hour time, using am or pm.
- 15:30 is after 12:00 midday, so it is a pm time.
- Take 12 away from the hour: 15 − 12 = 3.
- 15:30 is 3:30 pm.
Answer: 3:30 pm