The equation for computing loan interests is Monthly payment = [rate + rate / ( (1+rate) ^ months -1) ] x principal loan amount. A subsidized loan is one when the government actually pays the interest when the student is enrolled in the college and taking proper classes. An unsubsidized loan has interest added to their loan while they are enrolled and going to college. A Credit Union is a member-owned financial co-operative. These institutions are created and operated by their members and profits are shared among the owners. Lastly, the definition of a bank loan is the amount of money loaned at interest from a bank to a borrower.