How many times have you heard "it must be right because that's the value the computer came up with"? Well, computers sometimes make errors when they do arithmetic. There are round off errors, overflow errors, etc. See what you can find online regarding the various types of errors that computers can create when doing arithmetic, or share some you may have experienced yourself. What about programs like Microsoft's Excel that perform a lot of math calculations? What types of errors have you experienced using those types of programs?