Let’s say you are trying to find the present value of a five-year stream of $1,000 in cash each year, and you’ve determined that the discount rate is 5%. The formula you would use for each period is present value = CF / (1+r)n where CF is cash flow, r is discount rate, and n is the number of periods.
If you were trying to determine the present value of the cash flow above using this formula, you would get $952 for year 1, $907 for year 2, $864 for year 3, $822 for year 4, and $784 for year 5, making the total present value $4,329. This is ess than the sum of the future cash flow, which is $5,000.