Joonmyeon is a mathematics professor who can seem to solve everything but the motive of the cheeky student sitting in the back of his classroom.

Preview: 

“Professor Kim? Are you a 90 degree angle?”

    “I don’t understand–”

    “‘Cause you look right for me.”

And Joonmyeon groaned for the nth time that day, feeling another white hair sprout on the back of his head.