Hi, my name is Bassem Saad. I'm a Math Ph.D. candidate at U.C. Davis, and I'm here today for About.com to show you how to calculate an average.In mathematics, an average is a way of finding a typical value out of a set of data. For example, the average grade on an exam, or the average weight of an American adult. There are at least three different types of averages: they are called mean, median, or mode. In this video, I'll show you how to calculate the mean.Say you wanted to find your average exam score and you've taken five exams. Well, the first thing you do is you add all five exams: 32, plus 40, plus 23, plus 25, plus 25, equals 145. Then, you know you've taken five exams, so you divide 145 by the five exams, and you get 29. Your average exam score is 29.The average is a great way of compressing a massive collection of data into an easy-to-understand number. They're used regularly in opinion polls, surveys, and medical research.Thanks for watching, and to learn more, visit us on the web at About.com.