So you're a business tycoon. Or maybe not. Surely there are times when you wish you could do simple calculations involving percentages, such as: 1. Calculating wage increases 2. Calculating discounts or tips 3. Figuring out how much revenue you'd make at a sustained rate etc. 4. Calculating VAT, Taxes and so on And of course there are times when you'd want to do equations involving simple algebra: You've got two 'knowns' and you need to figu...