Banks often advertise continuous compounding of interest on savings accounts, by which they mean that interest is added continuously to the account at a rate equal to the product of the current account balance and the annual interest rate. (Interest rates are always advertised in percentages, so the proper rate to use for calculation is the advertised rate in percent divided by 100.) Compare the return after one year of continuous compounding at 5 percent to the return with annual, semiannual, and quarterly compounding.