Console. Convert int to time

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

We're not in the business of doing homework problems. If you make an attempt to do this on your own, we'll be more than happy to help if you get stuck on certain parts.