You probably were first introduced to the time value of money in college or in a job training program using equations such as these:
where FV = future value, PV = present value, i = interest rate per time period, and N = number of time periods to maturity.
The two equations are the same, of course, and merely are rearranged algebraically. The future value is the present value moved forward along a time trajectory representing compound interest over the N periods; the present value is the future value discounted back to day zero at rate i per period.
In your studies, you no doubt worked through many time-value-of-money ...