James A. Calderwood has been elected president of the University of Maryland Alumni Association International, which represents about 200,000 Maryland graduates. Calderwood, a member of Maryland's Class of 1964, is a partner in the Washington law firm of Grove, Jaskiewicz, Gillian and Cobert. He lives on Hillandale Road in Chevy Chase. Perfect Mathelon Score

Takoma Park Intermediate School eighth-grader Sarah Manchester finished with a perfect individual score in the first annual Mathelon, a recent statewide math competition in Baltimore sponsored by the Maryland Council of Teachers of Mathematics. About 50 junior-high level students participated. Two other Takoma Park students, eighth-graders Josh Fischman and Brian Miller, were also among the competition's top six scorers. The students' teacher at Takoma Park is Darlyn Counihan. Student Auto Courses

Robert Fogarty, president of Sport Chevrolet in Silver Spring, has been chosen for the second year to sponsor the Montgomery County Public Schools' automotive career program. Students will work at Fogarty's car dealership and others for credit and receive hands-on training in auto mechanics, sales, bookkeeping and advertising. Fogarty lives on Albemarle Street in the District. New Board of Realtors President

Harvey Rosendorf, owner of Harvey Rosendorf Inc. Realtors in Bethesda, is the new president of the Montgomery County Board of Realtors. Rosendorf, also a builder, has been a member of the board since 1973. He lives on Willard Avenue in Chevy Chase. Computer Science Award

Jack Minker, a University of Maryland computer science professor since 1967, received the 1985 outstanding contribution award from the Association for Computing Machinery. The 40,000-member international organization recognized Minker's decade-long human rights fight on behalf of several Soviet scientists and computer science colleagues. Minker lives on Millwood Road in Bethesda.