who played mr dewey on saved by the bell
Patrick Thomas O'Brien Patrick Thomas O'Brien (born January 26, 1951) is an American actor. He is perhaps best known for playing the role of Mr. Dewey, the math teacher from Saved by the Bell.
Mark-Paul Gosselaar Mark-Paul Harry Gosselaar (/ˈɡɒslər/;[1] born March 1, 1974) is an American actor. He is known for his television roles as Zack Morris in Saved by the Bell, Detective John Clark in NYPD Blue, and Peter Bash in Franklin & Bash.