Ann Trenk '85 sat down in the Science Center Saturday morning, took one look at the test, and thought. "I have no idea how to do these problems, and I have to sit here for at least three hours doing them."

The Currier House resident was one of about 70 undergraduates competing in the 43rd annual Putnam Mathematical Competition, a nationally administered contest.

Trenk and most of the others were taking the exam out of curiosity or for fun, but three Harvard students were playing for high stakes: national awards, individual honors, and a scholarship for graduate study of mathematics.

While many of the participants said they were dazzled by the complexity of the essay-type problems, the trio representing Harvard was apparently unfazed.

"Math 21 is all you need to know," said team member Michael P. Larsen '84, who finished in the top five nationally last year and also won the Putnam Fellowship from Harvard's Graduate School of Arts and Sciences.

The six-hour test "does not stress acquired knowledge," but ingenuity, said Benji Fisher '85, who finished sixth in the nation last year.

Also representing Harvard was Michael Raship '83, who took sixth place two years ago.

Harvard Math Professor Andrew M. Gleason, who as an undergraduate at Yale finished in the top five for three consecutive years, said yesterday that "you can dubble around, but [studying for the test] won't do a great deal."

Glearson, who now selects the annual recipient of the Putnam Scholarship, said that "only six or seven schools all over the country have any prospect" of winning the contest.

A team from Washington University in St. Louis took the first place honors last year. Harvard's representatives finished third in the competition sponsored by the Mathematics Association of America.

The results of this year's test will be announced in March. "No one gets a perfect score, ever," said one first-time contestant.