How to add hours and half-hours to a time:

• Add the number of minutes together. If the minutes are 60 or more, subtract 60 from the minutes and increase the number of hours by one.
• Add the number of hours to the hours portion of the time.
• If the number of hours is more than 12 do the following:
  • Subtract 12 from the number of hours.
  • If the time was AM change it to PM, if it was PM change it to AM.
  • Repeat this process if the number of hours is still more than 12.
• If the number of hours is equal to 12 change AM to PM or PM to AM.

Example: What time is 17 hours and 30 minutes after 3:30 AM?

• The sum of the minutes equals 60. Subtract 60 from the minutes and increase the hours by one to 18.
• Add the hours together. (18 hours + 3 hours = 21 hours)
• If the number of hours is more than 12 do the following:
  • Subtract 12 from the number of hours. (21 hours - 12 hours = 9 hours)
  • Change the AM to PM.
• Answer: 9:00 PM