On Jan. 24, the Department of Mathematics and Statistics hosted Arthur T. Benjamin, the Smallwood Family professor of mathematics at Harvey Mudd College, for his “Mathemagics!” presentation, as well as a talk for the department. Benjamin is the author of several popular books, including The Magic of Math: Solving for x and Figuring Out Why, which were featured in three TED talks and appeared on television, radio and print.
Both events were part of the department’s “Math Monday” series, in which faculty, visitors and students give presentations related to mathematics. This year, the series is organized by Professor of Mathematics Nuh Aydin with logistical assistance from Emily Teater, administrative assistant in the academic division. While frequently held on Mondays, as the name suggests, this week’s presentation was changed to Wednesday to accommodate Benjamin’s schedule. His presentation, titled “Counting on Students: Combinatorial Proofs with Undergraduates,” consisted of a selection of combinatorial proofs, including clever alternatives to traditional introductory proofs.
Benjamin began his “Mathemagics!” presentation with a card trick involving an invisible deck, followed by a demonstration of his ability to quickly mentally square two-, three- and even four-digit numbers, checked by four audience volunteers using their smartphones. He then asked audience members to tell him the date of their birthday, including the year, and provided them with the day of the week they were born on. Then, he created a magic square, a four-by-four grid filled with numbers such that they add up to the same value in different ways, using the birthday of an audience member.
The presentation was followed by a Q&A session, where Benjamin answered questions ranging from his background and inspirations, to revealing the methods behind his lightning-fast mental calculations to explaining the phonetic code he uses to memorize long numbers. Next, he put his memorization skills to the test, first writing out the first 60 digits of pi using wacky mnemonic sentences (such as “have a baby fish knife so Marvin will marinate the goose chick”) and then answering increasingly difficult questions from an audience member he had provided with a book of the first 10,000 digits of pi. Finally, he performed a rendition of “Mathematical Pi” to the tune of Don McLean’s “American Pie.” The event drew a wide range of attendees, including faculty and their family members, community members and students from many majors. In an email to the Collegian, Aydin discussed the benefits of mathematical talks geared toward wider audiences: “Mathematics is the universal language of the universe. [It] is both stunningly beautiful and extremely useful. It is an indispensable tool for many disciplines,” he said. “A liberally educated person should not be ignorant of mathematics. […] We encourage everyone to think about mathematics in this way.”