The Mathemagician

| July 27, 2011

Quick, what’s the square of 7?

49, right?

Now, what’s 49 squared?

Dr. Arthur Benjamin.

Dr. Arthur Benjamin.

Most of us can’t answer that one without a piece of paper or a calculator, but Dr. Arthur Benjamin can – and at lightning speed.

“I’m a professor of mathematics at Harvey Mudd College in Claremont, Calif., and I’m a professional magician,” he said. “And over the last 30 years or so I have been combining my passions of math and magic to do what I call ‘mathemagic.’”

Benjamin does complex math problems in his head, and in many cases, faster than a calculator.

Next week, he’ll bring his show to the River City as Louisville Collegiate School presents “A Night of Mathemagic” at 6 p.m. on Friday, Aug. 5.

Benjamin squares three-digit numbers at a mind-boggling rate.

With calculator in hand, this writer tested him. The square of 753?

“That’s 567,009,” he said without a pause.

He also squares four- and five-digit numbers, though, by his own admission, not quite as fast as a calculator. Among his other feats, if you tell him a date, even going back to the 1800s, he can tell you what day of the week it was.

This writer was born on a Thursday. I knew that and, almost instantaneously, Benjamin did too.

“The goal of my show is not for the audience to see how smart I am, but rather how smart they can be,” he said. “Whereas most magicians don’t reveal their secrets, mine are mathematical, so I’m happy to share them.”

Benjamin also shares his techniques in his book, “Secrets of Mental Math.”

Dr. Benjamin teaches at Harvey Mudd College.

Dr. Benjamin teaches at Harvey Mudd College.

“Everyone will come out of the show learning how to improve their ability with numbers, and pick up a few amazing skills along the way,” he said.

When computing complex problems, Benjamin uses phonetic codes to remember larger numbers.

Mathemagic “is very much a skill like typing or juggling or playing a musical instrument – these aren’t things you might be able to do spontaneously, but if you practice and you practice the appropriate way, these are things that everyone can do,” he said. “The more you practice, the better you will be.”

Benjamin is no “Rain Man,” although he has “definitely, definitely” seen the movie, which featured Dustin Hoffman as an autistic savant with amazing mathematical and memory skills.

“There do exist autistic savants that have these special skills that come at the expense of having an otherwise versatile brain,” he said. “What I’m doing is something that I can explain. It’s something that anyone can learn.”

It doesn’t take a great memory to do mathemagic.

“My visual memory is really pretty average, and my memory for names and faces, I would actually describe as being pretty poor,” Benjamin said.

“I’m extremely absent-minded,” he added. “Even as an adult, I would be described as ADHD, somebody who is very easily distracted. I’m pretty good at concentrating in bursts – that helps when doing large calculations. I have what you might call a trained memory.”
Benjamin, 50, has been teaching math at Harvey Mudd since 1989. His visit to Collegiate coincides with the annual Mathematical Association of America’s MathFest in Lexington where he will be speaking.

Originally from Cleveland, Benjamin always has loved math.

“I’ve had a love of numbers for as long as I can remember,” he said. “I just found the consistency of arithmetic to be absolutely beautiful and I still do today.”

He began developing his mental computation skills in high school.

“I would take problems apart and try and solve them in different ways,” he said.

Benjamin went on to earn his bachelor’s degree from Carnegie Mellon University and his master’s degree and Ph.D. from Johns Hopkins University.

But it isn’t all just fun and games for Benjamin. As a lifelong lover of math, he worries that many students aren’t being allowed to develop a love for numbers.

“Most of the people teaching math in elementary school were math-phobic,” he said. “I worry that they are passing that math-phobia on to their students.”

He believes that elementary school math should be a speciality course, such as art or music, where teachers are typically passionate about their subjects. And in high school, calculus shouldn’t be the ultimate goal.

“If there needs to be a top of the pyramid, it would be much better if it were probability and statistics,” he said. “That’s a subject that you can apply in your daily life.

“A scientist, or an engineer or an economist might use (calculus) a little bit in their work, but it’s not something they bring home with them, whereas probability and statistics – understanding randomness, risk, uncertainty – are things we actually do encounter on a daily basis, and the ability to cope with that and understand that can provide lifelong benefits.”

If You Go

“A Night of Mathemagic” with Arthur Benjamin
6 p.m. Friday, Aug. 5
Louisville Collegiate School, 2427 Glenmary Ave., in the school’s auditorium
Admission: $5 for adults and free for children
Info:, 502.479.0340

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Jacob Glassner

Jacob Glassner, News Editor/Plate Spinner

Jacob usually has his eyes glued to a computer screen, editing stories and making sure the paper gets out the door each week. Multi-tasking is his modus operandi – similar to the plate spinners you’d see on the old “Ed Sullivan Show.” Turn ons: freshly-sharpened pencils. Turn offs: exclamation points!!!

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