Absolute Value of Romance

A youth romantic comedy about a high school girl who writes 19+ rated BL novels about her handsome male teachers, but ends up falling in love with her math teacher and becomes the protagonist of a turbulent romance.
Yeo Ui Ju is a 19-year old average student intimidated by her overbearing mother and lives by the rule of staying out of the spotlight at school. However, her creative drive is fueled by a dangerous imagination brimming with inner conflict. A lifelong single with no real-life romantic prospects, she believes it's safer to enjoy love only through her imagination.
No Da Ju, the son of a bank president and an English teacher at a girls’ high school. He likes attention, talks a lot, falls in love quickly, and gets dumped just as fast. He has been friends with Ga U Su, the math teacher, since elementary school. Ga U Su’s a cold, handsome man who rarely smiles, and a math prodigy who learned to calculate before he could even speak. He has a remarkably good memory, and enjoys playing the piano.
(source : mydramalist)