The Facts of Life (1979)

S3E20 Kids Can Be Cruel

Natalie is head over heels for Tim and has showered Blair's slambook with compliments about him. In this slambook, instead of writing their names, friends sign a number, and Natalie's is 10. When Blair reveals to Tim that number 10 belongs to Natalie, she becomes enraged and vows to get back at everyone, regardless of who gets caught in her crossfire.