I think the only reason I stayed in school is because I didn't realize there was another option, and staying in school allowed me to avoid the real world which is even more terrifying.
In the real world one rarely uses anything more complex than addition, subtraction, and multiplication -- all done on a calculator, of course. I use a financial calculator to do things like figure return on investment, but again this is something nobody would ever do with pen & paper.
I have a BS in Business Administration and graduated with honors. How much has this degree earned me? Absolutely nothing. How much did it cost to get this degree? About $10,000 (back in 1991-95). As a finance major, I'm fully qualified to say this was a very poor return on investment.