I am currently dealing with problems in which I need to find the difference between different times. One trick that worked for me until now was from here a short summary of which is
For Adding Times Add the hours Add the minutes If the minutes are 60 or more, subtract 60 from the minutes and add 1 to hours For Subtracting Times Subtract the hours Subtract the minutes If the minutes are negative, add 60 to the minutes and subtract 1 from hours.
However this trick logically fails when I attempt to subtract
5:00 PM - 12:00 PM (Ans 5 hours)
Also does anyone know how we can calculate differences like (2 AM - 5 PM (Day Before) ) Is the best way to calculate time difference to convert it in 24hr clock first ? I am actually in need of some speedy shortcuts for calculating these differences since I wont have a lot of time on my hands while solving these problems during a standardized test.