How to subtract days and hours.

- If the number of hours being subtracted is more than the original hours, do the following:
- Subtract 1 from the original number of days.
- Increase the number of original hours by 24.

- Subtract the hours.
- Subtract the days.

Example: What is 4 days 11 hours minus 2 days 17 hours.

- The original number of hours (11) is less than the 17 hours being subtracted so:
- Subtract 1 from the original number of days. (4 days - 1 day = 3 days)
- Increase the number of hours by 24. (11 hours + 24 hour = 35 hours)

- Subtract the hours. (35 hours - 17 hours = 18 hours)
- Subtract the days. (3 days - 2 days = 1 day)
- Answer: 1 day 18 hours