What is the present value of a single future sum

For this you want to know how much money do I need to invest now to have a certain amount in the future: For example how much do I need to invest now If I want a $15,000 down payment on a car 5 years from now.

You need to know the interest rate, Number of periods, and the future amount needed.

For the interest rate you take the annual rate / by the number of periods in one year to get the right rate.

For number of periods you take the number of periods of interest in a year * number of years.

For example 12% interest compounded quarterly will be 12/4 = 3% and the number of periods will be 4 * the number of years.

how is present value of a single sum and present value of an annuity related