Since I don't use the percent sign. Here is instead a MUCH easier way. Divide the price you bought it for (289) by the original price (648). This gives you the percentage that 289 is with respect to 648 if you just read off the first two decimal places. When you divide one number by another it will tell you how many times they 'fit' for the purpose of explaining it. That is also essentially what a percentage is out of 100 parts. so when you divide one number by another, you will get a decimal answer, just multiply it by 100 (or just take the first two decimals) and that is percent saved (percent different). Note that if the first value is LARGER than the second, you will have a percentage of over 100%.