Present value

The value today of a stated amount of money you receive in the future.  It is calculated by dividing the stated amount of money by 1 + the interest rate adjusted for the length of time, t, between the date the calculation is done and the date the payment will be received.  This adjustment is accomplished by raising (1+i) the tth power.  Specifically, the present value at an interest rate of I of $X received in t years is: