Here is a trick that i got from online

Adding Times

Follow these steps:

- Add the hours
- Add the minutes
- If the minutes are 60 or more, subtract 60 from the minutes and add 1 to hours

Subtracting Times

Follow these steps:

- Subtract the hours
- Subtract the minutes
- If the minutes are negative, add 60 to the minutes and subtract 1 from hours.

Problem :

However this trick does not work when i need to subtract:

5 PM from 12:00 PM (What happens now)

and also what should i do if i need to subtract 2AM of one day with 5 PM of the day before ?

Any tips or tricks ??