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Call us the math media Your article April 28 about "Trying to think like a fifth-grader" was interesting. Question 3 asked about how many games would be played in a tournament with five teams if each team played each other once. The answer was 10. If there were 100 teams, how many games? -- John L., Medford What do we look like, John? We're journalists, not mathematicians! Actually, we've received quite a few questions about the questions, especially Question 3. Several callers insisted the correct answer is not 10. Well, the answer is 10. And a look at why 10 is the right answer for a five-team tournament will help explain how you get the right answer for a 100-team tournament. With five teams, each team will play four games. Five teams, four games, 20 games total. But that total still counts each game twice (it counts the combination of Team 1 playing Team 2, as well as Team 2 playing Team 1.) So, you need to divide by two. Answer: 10. The formula for arriving at that answer is n times (n minus 1) divided by two. For the math literate, that's n squared minus n over 2. So, 100 teams into the formula. Multiply 100 times 100; that's 10,000. Subtract 100, leaving 9,900. Divide by 2. Answer, 4,450. We have some pretty whizbang editors here (well, one anyway), but to doublecheck our math we went to an expert. Sherry Ettlich, chairman of the math department at Southern Oregon University, to be exact. She confirmed our math. And she said one way to visualize the problem is to picture a circle. Each team is one point on the circle. Draw lines connecting each point with all the others. Now, count the connections. Five points, 10 connecting lines. Five teams, 10 games. A bunch of callers expressed interest in the tests and the questions. The questions we excerpted were the most interesting and challenging from the fifth-grade sample test we took. There were some simple, easy questions on the test, but we didn't reprint those. To see a sample test, or to find out more, anyone with Internet access can go to the state Department of Education's Web site, www.ode.state.or.us Now, about Einstein's theory of relativity ... ("Since You Asked'' is a daily feature in the Mail Tribune that answers questions from readers on virtually any topic of general interest. To submit a question, e-mail us at [email protected] Please include your name, address and phone number for verification. If you have specific questions about our Web site or other questions about the Mail Tribune, please send them to [email protected] ) Today's Edition : News | Sports | Business | Weather | Tempo | Classifieds Mail Tribune Copyright � The Mail Tribune 2000, Medford, Oregon USA