Profit

I just bought this silly little app. Its ok but doesnt have what I need for my biss. I want to be able to calculate backwards, for example. I sell something and I want to mark it up 30%, I divide my cost by 70 and I hit the percent symbol, that will give me my 30%. Now I want to be able to later on look at any product that I sold and apply a formula to that cost and tell me how much I made on that product by using the percent I use to mark up the item I sold.

Comeaway about Percentages - Percent Calculator, v1.81