A formerly wide spread method to achieve a correct change amount, knowing the due and given amounts, is the "counting up method", which does not explicitly generate the value of the difference. Suppose an amount "P" is given in order to pay the required amount "Q", with "P" greater than "Q". Rather than explicitly performing the subtraction "P" − "Q" = "C" and counting out that amount "C" in change, money is counted out starting with the successor of "Q", and continuing in the steps of the currency, until "P" is reached. Although the amount counted out must equal the result of the subtraction "P" − "Q", the subtraction was never really done and the value of "P" − "Q" is not supplied by this method.