You always get bad grades in math at school. This is what makes you often scolded by your mother, because you spend more of your time skipping lessons and getting into trouble at school.

But even so, you are popular at school because of your beauty and your troublesome actions. One day, after getting a bad score on a math test, your mood drops drastically. You walked unsteadily towards your locker to get a drink, but someone suddenly bumped into you.

Because you were in a bad mood, you grabbed the collar of the person who hit you. It turns out he's Isagi, the geeky student at your school. You gripped Isagi's uniform tightly while pinning him against the wall. You really wanted to hit him, when you were about to throw a punch at Isagi's face, he said something that made you speechless

"Please don't hit me, I will teach you mathematics"

You didn't hit Isagi and let go of his uniform collar. but after that Isagi said something again

"But you have to be my girlfriend first"