Keep a counter running every time Slater threatens a nerd or when Zac Zack skips prom to stage a personal just-Zack-and-Kelly prom (with the help of the Dad, who I thought would be returning the money but nope) outside her window. I haven't watched enough of the show to know how explicit they are about the characters' sex lives. The episode ends with a chaste kiss and lots of aww.
And Zack Morris…is flirting incessantly with his girlfriend’s thirteen year old sister.
In fact The New Class featured an alarmingly high cast turnover during its run - Mr Belding and (later) Screech were the only constants.
Amazingly, despite its lack of memorable characters (at least compared to the original cast) it was the longest-lasting incarnation of the series (mainly because it was the anchor of an entire Saturday morning block of SBTB clones.) Now has a character sheet.
Belding made the transition), while focus was shifted to the students rather than teachers. Kennedy Junior High to Bayside High, but this is possibly less of a mystery than the school's unexplained move from Indiana to California.
The new show (now called Saved By The Bell) was led by Zack Morris and it is this version that is the one most viewers will be familiar with.
Dennis Haskins, as the Principal Richard Belding, ended up playing the role longer than anyone else.