Arthur Benjamin was ready to let the crowd in on his secret.
He’d just amazed students in The Blake School auditorium by asking them their birthdays and telling them instantly the day of the week they were born on. The math-based trick works by assigning certain numbers to the years, months and days—and it doesn’t just work with recent years.
“That actually goes to (the year) 1600—because you never know with some of these teachers,” Benjamin joked during Monday’s show.
Benjamin is a math professor at Harvey Mudd College who is also a self-described “mathemagician.” He wows audiences with a blend of math feats and magic tricks.
Benjamin’s presentation isn’t just about cool party tricks, though. He oozes an enthusiasm for the process of math—seen when one student asked whether he discovered the feats he performs.
“These ideas for calculating numbers quickly are hundreds and thousands of years old, but I had the pleasure of finding it out for myself,” Benjamin answered.
Magicians are renowned for not revealing their secrets, and Benjamin is equally tight lipped on illusions that fall strictly within the realm of magic. But with his passion for numbers, he happily explains the mechanism behind his math feats.
The Blake School stage had an easel and paper waiting for Benjamin. In one trick, he began by asking a student named Emily for her birthday and writing the numbers in the top line of a magic square—a four-by-four grid in which every line adds up to the same number. Within seconds, he completed the square.
Later in the presentation, he walked the students step-by-step through what seemed at first to be an impossible achievement.
“The truth of the matter is most magic tricks are very simple, and the magic square is no exception,” he said.
After the presentation, Benjamin visited classrooms and talked to students in smaller groups. While he filled in magic squares and quickly squared numbers in his head on stage, in the classroom setting he helped students with the more-mundane problems they face in their homework.
Student Rari Chepuri said enjoyed math even before he got to see Benjamin. He’s a seventh grader who’s quick to note that he’s in eighth grade math. Still, Chepuri said Benjamin added an extra bit of excitement to the subject.
“This made math sort of seem fun, and you can use these tricks in your math class,” Chepuri said.
Check out the video above to see Benjamin perform one of his math tricks and then explain how he did it. When you’re done, click on the YouTube video to watch his world-famous TED talk.