Evan O'Dorney, 17, took home $10,000 in the math game "Who Wants To Be A Mathematician?"
It's a repeat performance for Evan. Last year, he won the same contest, which was held here in San Francisco.
"I don't know why I'm that good at math other than the fact that I was born that way. But if I have a problem I am pretty good at explaining how the methods work," said Evan.
Evan is home schooled and he's also a national spelling bee winner.
He plans to go to Harvard in the fall to study to be a math professor.