## Semi-Mathy Games

December 14, 2011 4 Comments

Here are some silly semi-mathy things I’ve done with my students either as bonus problems or fillers. I cannot vouch for their pedagogical value.

**+1 or +3.**A bonus question appeared at the end of a test. “Write*Free +1*and you’ll get a bonus point on the test, no questions asked. Or write*Go For +3*and if two-thirds of the class does it, all who do will get 3 bonus points. Saying anything out loud voids the bonus for everyone.” I was pretty surprised that in most classes, not enough students went for the +3. One student wrote*Free +3*and got nothing…**Choose A or B.**In class, students were given this choice: “Write*A*and you’ll get a point for everyone in the class who writes*A*. Write*B*and you’ll get twice as much as anyone who writes*A*.” After a long debate, most students picked*B*. Far fewer students picked*B*when the choices were revealed publicly instead of privately. (Social commentary followed…)**The probability you’ll get this question right.**Still one of my favorite bonus problems of all time, this came from my wife: “If train A leaves Denver at 50 miles per hour, and train B leaves Chicago at 60 miles per hour, what is the probability that you’ll get this question right?” Students who wrote 1 or 100% were right, students who wrote 0 were wrong, and anything in between was resolved with a coin or random number generator. (There’s a fun discussion over whether a student who writes 0 can be right by being wrong… but if they’re right then they’re wrong…)**The dollar auction.**This one is evil. See http://en.wikipedia.org/wiki/Dollar_auction for a full description. In one class, a student successfully “escaped” by outbidding the other player significantly. In another class, a third student jumped into the auction midstream allowing another to escape. If I were still teaching, I would repeat the process using the bidding systems by Beezid and other “penny auction” sites (http://en.wikipedia.org/wiki/Penny_auction). Hopefully by exploring these auction styles with students they will avoid being scammed for real money later in life.

What else?