After years of practicing and dreaming, Xiaosheng Mu ’13 became one of the top five scorers in the 2009 William Lowell Putnam Mathematics competition — a competitive exam offered to over 3,000 college undergraduates in the United States and Canada. He is the first individual Yalie to make the top five since 1989, though a Yale team placed fifth place in 1991.

“I dreamed of winning the competition in high school,” Mu said. “I felt contented that I had finally managed to achieve what I have been striving for.”

[ydn-legacy-photo-inline id=”7415″ ]

[ydn-legacy-photo-inline id=”7416″ ]

[ydn-legacy-photo-inline id=”7417″ ]

Mu, who hails from China and said he has a “zeal for math,” has participated in many math competitions, including the 2008 International Math Olympiad in Madrid, where he represented his country — and won the gold.

The Putnam was held last December and is administered by the Mathematical Association of America. Universities throughout the United States and Canada designate teams of three members, though other participants can register independently as well, as Mu did. Awards are given for both team and individual scores, though Mu said he does not know what his score was. Mu’s win is “marvelous,” said Roger Howe, director of undergraduate studies of mathematics.

“The glory goes with you forever; it’s like an Olympic gold,” said Steven Dunbar, a professor at the University of Nebraska, Lincoln, and a member of the Committee on American Mathematics Competitions, which advises the Mathematical Association of America.

Mu said he found out about the competition during his senior year of high school, but said he did not think that he was ready at that point because the test requires extensive problem solving skills and technical knowledge.

“The problems don’t necessarily require advanced mathematics but do need a lot of imagination, creativity and insight to be solved,” explained Max Engelstein ’10, who scored in the top 200 on the Putnam and co-president of the Yale Undergraduate Mathematics Society.

Mu started preparing this fall, when he took linear algebra and advanced calculus. He began working through past exams. After taking the exam, Mu said he felt good about it, but days later he started having doubts as he tried to review what he had written.

Still, he said, he realized he should not let the results undermine the fulfillment of participating in the competition and being challenged. In the end, he said, the results came as a surprise, as he had only hoped to be in the top 15.

But despite his achievement, Mu said he tries to balance his life with other activities. He enjoys singing, playing sports and competing in intercollegiate pool. And although he works hard, he said he strives to keep his life as stress-free as possible.

“I try to not do too much work on weekends,” he said.

About 20 Yalies participated in the 2009 competition; two were ranked in the top 200 and another four ranked in the top 500. The participants met every week for practices organized by the Yale Undergraduate Mathematics Society, though Mu largely studied on his own. The team was chosen by Howe, based on how well previous test-takers scored.

The prizes range from $25,000 for the top team to $5,000 for the last team. This year, the top five teams were from the Massachusetts Institute of Technology, Harvard University, the California Institute of Technology, Stanford University and Princeton University.

Correction: March 25, 2010

An earlier version of this article misstated the prize for the fifth-place team in the William Lowell Putnam competition, which gets $5,000, while each individual team member receives an extra $200.