Present Value of a General Annuity

This video shows an application problem in which we need to compute the present value of an ordinary general annuity. It shows how to store the periodic value of the periodic rate of interest in the memory of a scientific calculator (I use here the Sharp 520), and how to use later the stored number for computing the present value of the annuity. The problem explained is the following:
An installment contract for the purchase of a car requires payments of $252.17 at the end of each month for the next three years. Suppose interest is 8.4% p.a. compounded semiannually.
What is the amount financed?