(original value) + (percent increase)*(original value) = (new value) (original value)(1 + (percent increase)) = (new value) (original value) = (new value)/(1 + (percent increase)) Note that "percent increase" may be expressed as a percentage or its equivalent decimal fraction. Example Find the original value if the amount is $60 after a 20% increase. (original value) = $60/(1 + 0.20) = $(60/1.2) = $50