J.S.
Save your sanity and plug it into excel. Look under formulas and financial.
I am an accountant but after a day of it the last thing I want to do is remember something I do not practice. When I need it, I use excel.
Look for present value of future cash flows, I think. I don't have excel on this machine for a reason.
Actually my work is so much harder than time value of money but I love it because it changes every day! If you have the ability add information technology management or management information systems or whatever they are calling it these D.. Basically business IT. I go between analyzing advising and forensics. Could not ask for a more challenging, and not boring, career!