Complex sentence: He was captain of the math team at Stuyvesant High School and an IMO Silver Medalist for the United States, graduating from high school in 1974 and then attended Princeton University, where he graduated in 1978 as valedictorian.
Split into simpler sentences: He was captain of the math team at Stuyvesant High School and an IMO Silver Medalist for the United States, graduating from high school in 1974. He then attended Princeton University, where he graduated in 1978 as valedictorian.