There is a bug in the new version of Microsoft’s Excel: 77.1*850 should give 65,535 but gives 100,000 instead. Joel Spolsky explains in great detail and, being a programmer on the Excel team in the past, apologetically the inner workings of the program that lead to this behavior. If you do not want to read the whole article: it’s merely a bug in the way the numbers are displayed, not calculated.