I need in a console application to have user input 1300 or 1330 and have that be converted somehow to 13:00 and 13:30 instead of 1330 the pure number.

So that I can then take 1330 and have the user input an end time like 1430 and increase it by 25 percent to come out with 1445 or 2:45

The input will always be HHMM in military time