  By Sarah Weld
When Nico Brown turned 11, his closest pals joined him for what his dad remembers as his best birthday ever. A mathematician—not a magician—entertained the kids with an 11dayold unsolved problem in dynamical systems at the Mathematical Sciences Research Institute above the Cal campus. After tackling that together, the guests took in a lecture about how math animates Pixar movies. The festivities moved to La Val’s Pizza on the geometrically named Euclid Avenue, where the kids shared a pizza with a “pi” cutter before ending with a geometry session at their weekly math circle—a logical end to a fullon math bash.
Brown, now 13, and the other party guests all study math at the Berkeley Math Circle, a weekly twohour program held in Evans Hall at UC Berkeley for more than 250 Bay Area elementary, middle, and high school students. Based on an Eastern European model—the first math circle started in Hungary more than 100 years ago—math circles offer students the chance to delve more deeply into concepts they can’t explore readily at school, taught by professional mathematicians such as professors and graduate students. Eventually, the Hungarian model spread through Eastern Europe and Asia, producing many successful scientists and mathematicians. Some experts believe that math circles in Russia, Bulgaria, and Romania once helped children from those countries consistently outperform Americans on the International Mathematical Olympiad. Over the last 15 years the U.S. competitors have greatly improved thanks to an increase in international coaches, math circles, and summer camps.
Berkeley Math Circle kids, called circlers, range from those bored by their regular math classes and seeking more challenge, to those who adore math and want more, to those whose math knowledge already surpasses their teachers’. There are no grades or mandatory tests; all that’s required is a love of math.
Sponsored by the UC Berkeley Math Department, and helped by the Mathematical Sciences Research Institute and parents, the Berkeley Math Circle costs about $300 a year, “cheaper than babysitting,” says Director Zvezdelina Stankova, who also cofounded the Bay Area Math Olympiad.
On a recent Tuesday night, PoShen Loh, a visiting math professor from Carnegie Mellon University and coach of the USA International Math Olympiad team, energetically asks 50 middleschool students crammed into a stuffy classroom how many ways there are to make one team of 22 people from a group of 62. He reminds them that the team is like a bag of people; it can be arranged in any order.
Hands go up. Students toss out ideas. Loh covers the blackboard with equations and factorial symbols.
“It’s OK to be wrong in this class,” says Loh, wearing a bright purple shirt and perpetually smiling. “I spent all day being wrong. That’s what mathematics is all about.”
A few floors below and just down the hall from a group of Ph.D. students (Evans Hall is the math building for all ages), about 50 beginning fourth and fifthgrade students work through the evening’s problems with Cal graduate student Alexander Shapiro. (“In a long line, Bill noticed no woman stands immediately behind a man, and the first person in line is a man. Prove there are no women in the line.” “A cake is cut with a knife poisoned on one side. Prove that no matter how many cuts we make, there will always be a piece of cake free of poison.”) Various kids take turns at the board offering solutions. The room, hot and crowded with kids spilling out of chairs and onto the floor, is abuzz with chatter as students collaborate. During a break, some continue doing math, a few girls try to bend their feet back to their heads, one boy reads the latest Diary of a Wimpy Kid.
The classroom scene diverges from the typical school scene—there are not enough seats, kids chat—but veteran and novice circlers alike welcome the chance to do math with others.
“I like hanging out and talking about math,” says 14yearold Laura Pierson of Oakland, who joined the math circle in fifth grade. “[The Berkeley Math Circle] showed me a whole new side of what math was. I didn’t really know what math was before.”
Says her mother, Cindy Pierson, “It was lifechanging for her on several different levels. She got to meet other kids who shared her passion for math. To go from an isolating experience to a group experience was just wonderful for her. It’s nourished her.”
While our images of mathematicians may tend toward the solitary intellectual ruminating in a tower, circlers and “mathy” types say that image is far off base.
“It’s a lot more collaborative than people think,” says Laura Pierson, who, since beginning the math circle, has won silver medals in international competitions in China and Luxembourg as the youngest U.S. team member. Other math circle members have also excelled in competition. Fremont’s Evan Chen won the gold medal in the Asian Pacific Mathematical Olympiad last year. Evan O’Dorney of Danville, now a junior at Harvard College, won the 2011 Intel Science Talent Search, and the 2007 Scripps National Spelling Bee, and was a fourtime International Math Olympiad medalist.
But for most of these students, their competition results are simply a happy byproduct of their weekly hours in Evans Hall. As its name suggests, the Berkeley Math Circle truly encircles its students by providing mentors and weekly contact with professional mathematicians, as well as giving kids a place to explore math with their peers.
“Mathematicians love to work together,” says Ian Brown, father of Nico, the math birthday boy from Mill Valley who won first place in the Berkeley mini Math Tournament last year. “These kids need to be able to talk to people about mathematics. They need to find their kin. Once you’re identified by the tribe of mathematicians, they go out of their way to take care of you. For kids like Nico, the math circle experience is a lifeline.”
For Castro Valley’s Vincent Pisani, a small 12yearold wearing a black Beatles Tshirt who has made the honors list in several American Mathematics Competitions, “the math circle was a little beacon of light,” says his mother Susan Pisani, who regularly finds equationcovered graph paper strewn about the house. Before joining the math circle, “he was sort of on his own versus all of a sudden he has one arm around Laura and another arm around Nico. It’s just been an anchor. You just can’t get that anywhere else—the mentorship, role models, and having a circle of friends with the same passion.”
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So why, then, were there no math circles anywhere (except for Boston, which had the first in 1994) until 1998?
Because Zvezdelina Stankova was still in Bulgaria.
Stankova, lively and brownhaired with an infectious energy and enthusiasm for all things math, came to the United States to study math at Bryn Mawr College in 1989. She went on to receive her Ph.D. from Harvard University and ended up as a postdoctoral fellow at the Mathematical Sciences Research Institute and UC Berkeley. While at Harvard, she developed a passion for teaching, and continued on to earn teaching credentials in Massachusetts and then California, and gained insights into the limits of the American math curriculum.
“My passion is to work with kids who love math and want to see more, to open up their minds,” says Stankova, who has two children of her own, ages 8 and 6, and won the Mathematical Association of America’s Haimo Award for teaching college math in 2011. “In school, there is only a limited number of topics. In the math circles, the topics can be anything.”
In 1998, she founded the Berkeley Math Circle as a temporary model for teachers to start math circles at their own schools. The temporary part, though, has morphed into permanent. Without the government support that their Eastern European counterparts have, most teachers here cannot muster the resources or time to lead their own math circles. So, 16 years later, the Berkeley Math Circle—known as an “elite math circle”—has grown into one of the leading math circles in the country, inspiring more than 100 others nationwide, including ones in Oakland, San Jose, San Francisco, Pleasanton, San Ramon, and Marin County.
Stankova, 44, now a math professor at Mills College in Oakland and a visiting professor at Cal, remembers the moment in fifth grade in her native Bulgaria when a kind teacher believed in her and encouraged her to attend her math circle. After struggling with a regular class problem just three months earlier, Stankova went on to win the local math olympiad, to represent Bulgaria at the International Mathematical Olympiads, and then on to the United States to complete her studies. (Less officially notable but no less exciting, she also solved the last row of the Rubik’s Cube in the back of her parents’ car in fifth grade, while everyone else listened intently to the opening soccer game of the World Cup.)
In other countries the idea of learning collaboratively in a study circle is not limited to math. Stankova and her classmates participated in circles in chemistry, physics, biology, English, poetry, and literature throughout middle and high school, she says. Bulgarian parents regarded these circles as typical as afterschool activities like piano lessons or soccer. Here in the United States, most parents—or kids—have never heard of math circles.
Stankova’s mission is to inspire people to start as many math circles as possible around the country. Her fulltime job as a professor combined with raising two young children and running the Berkeley Math Circle does not leave Stankova much spare time. But it’s her baby, and as Ian Brown says, “Zvezda [her nickname] is the queen of the math circles.”
In fact, Brown, head of the Marin Math Circle, has been so impressed by his son’s experience in the Berkeley Math Circle that he just cofounded an independent mathfocused school in San Francisco, called Proof School, with University of San Francisco math professor Paul Zeitz. Stankova, along with other mathematicians Brown has met through Bay Area math circles—including MSRI Director David Eisenbud—is on the advisory board. Brown aims to open the school in the fall of 2015.
Brown began thinking about opening a math school during Nico’s math birthday party. “This should be these kids’ experience all the time,” he says. “They should feel this happy for large parts of their school day.”
A new school for math kids seems a logical result of Stankova’s math stamp on the Bay Area and the United States. From the first Bay Area Math Olympiad and the Berkeley Math Circle, to the Proof School and beyond, the young girl with her Rubik’s Cube has left her mathematical mark. And she’s not finished yet.
“I would not do any of this if I did not have a passion for it. Before I had kids I was doing it for the pure joy of it,” says Stankova, who teaches her 8yearold daughter, a Berkeley Math Circler, math from her old Bulgarian textbook. “Now I have an extra motivation to keep it going for my own kids.”
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Sarah Weld, former editor of The Monthly, is an Oakland writer and editor. 

(Top) Students, known as circlers, at the Berkeley Math Circle take up complex equations that often result in collaborative approaches for answers. (Bottom) Math maven: Zvezdelina Stankova founded the Berkeley Math Circle in 1998. Photos by Pat Mazzera.
mathcircle.berkeley.edu
mathcircles.org
A Decade of the Berkeley Math Circle: The American Experience, Volume I (2009, American Mathematical Society).

