mathlete
n. A person who competes in a mathematics competition.
Etymology
math + athlete
Examples
1999
When the mathletes are not doing math, they like to play "ultimate frisbee," Mr. Chui said. "It's very similar to football, except you can't run when you have the frisbee."
—Virginia Galt, “Teen 'mathletes' limber up for vigorous mental gymnastics,” The Globe and Mail (Canada), July 02, 1999
1998
The organization of high school and junior college math scholars has watched its membership rise to 50,000 mathletes and 1,300 chapters as interest in state math competitions has increased.
—Lini S. Kadaba, “However you want to figure it, math's popularity is increasing exponentially,” The Philadelphia Inquirer, December 28, 1998
1950 (earliest)
"Math meets" for "mathletes" are a monthly affair during the school year in Nassau County…

"Mathletes" are capable, and interested, students who participate in contests consisting of five rounds of competition..
—“Education Summary Vol 3,” Education Research Institute, January 01, 1950
Notes
This term isn't even remotely new, as the newly discovered earliest citation shows, but I'm going to leave it in the database anyway, for no other reason that I really love the word.
Filed Under
sciencepeople
Posted: July 02, 1999