STANFORD -- If any of the 246 registered contestants at Saturday's Julia Robinson Mathematics Festival had bothered to Google "famous mathematicians," they would have quickly put two and two together and concluded that higher math is a man's sport. Archimedes, Euclid, Pythagoras -- all giants with but one name and one X chromosome.

Sitting at the Card Mathemagic table in Stanford's McCaw Hall, Jodi McElvain, 11, didn't seem to give a fig about Isaac Newton as she attempted to amaze and bedazzle Iris Wu, 12, by using a complicated mathematical formula in which each playing card corresponded to a letter of the alphabet, and those letters spelled out her favorite ice cream flavor. M-I-N-T.

Jodi is an honors student in the sixth grade at Hausner Jewish Day School in Palo Alto, and there was nothing in the set of her jaw or the fierceness of her gaze that gave the impression she couldn't become a famous mathematician -- or a Las Vegas dealer -- if she wanted to. She held the deck in the palm of her hand, did some quick calculations in her head and pointed to the top card, telling Iris, "Wait, wait. This might be an ace. Or a seven. I think it's a four. No, no, it's an ace."

Iris and the table's adult proctor, Vineet Gupta, looked at the child quizzically as she toyed with them. When Jodi turned the card over, it was an ace. "Oh, look," she said with a sly smile. "I'm right."

The event was open to students in grades six through 12, and the only barrier to entry was summoning up the nerve to match wits with some of the Bay Area's best mathletes. Organizers provided no official tally, but it appeared the girls outnumbered the boys.

At several dozen large tables, a diabolical set of problems awaited a solution, each given a colorful title such as "Instant Insanity" or "Space Chips." Sydney McGillis, 15, and Frances Keer, 14, of Oakland's Bishop O'Dowd High School had landed at the latter table by midmorning and were searching for numerical patterns in plastic chips that were accompanied by a set of questions. Sydney said she "figured we'd just be sitting down listening to people talk," so she was relieved not to be spending her Saturday morning in a dreary lecture hall.

This was anything but that.

The heavy infusion of Y chromosomes was exactly what Nancy Blachman hoped for when she founded the festival in 2007, naming it after a not terribly famous math professor at UC Berkeley who solved Hilbert's 10th problem -- one of a renowned set of mathematical puzzles. "We thought if we named it after a woman," Blachman said, "girls would look into her and see that women can do math problems."

The problems posed at the festival tables were not exactly Hilbertian, but they also weren't based on large sets of dry numbers. "We try to expose kids to ideas that we think will be fun and engaging, and show them that math can be delightful," Blachman said. "That math is not necessarily what you see in your classroom."

Over the past decade, math proficiency in California classrooms has risen from 38.8 percent to nearly 60 percent, according to Adequate Yearly Progress figures. Brandy Wiegers, associate director of the San Francisco Math Circle, suggested events like Saturday's -- and a willingness not to simply "teach to the test" in some cases -- has made a difference. But she added that math skills still carried a hint of "dweeb."

"Because of that, students who do love math are a little bit scared to say it out loud and are very much pushed by their peers to not like math," Wiegers said. "As a culture, we have become more math illiterate. It's completely acceptable in a public setting to say, 'Oh, I'm horrible at math,' whereas no one's going to walk up to you and say, 'I'm horrible at reading,' or 'I'm horrible at writing.' That's not socially acceptable."

The Julia Robinson Festival is part of a push to remove math's stigma. "If you ask a second-grader to describe mathematicians, they look very much like princesses," Wiegers said. "They're wondrous people. By the time you ask a high school student who a mathematician is, they're very much nerds."

Of course, it doesn't hurt that the Bay Area is a place where math majors sometimes turn into multimillionaires.

Jodi McElvain counted out her reasons for attending as if she were doing simple arithmetic. "My parents wanted me to come here," she said, "plus I thought it would be fun. Plus I love math." Equals a good day.