None, that's what students are for.
They just work it out with a pencil!
They don't believe in higher powers.
Teacher: Why is your paper blank? Student: Sometimes silence is the best answer ! :D :D
Boy: Me and I'm going home now.
Student:I don't know. Teacher: Bark, my child, bark. Student: Bow, wow, wow.
He was already suspended.
Because X was always 10
She couldn't solve inequalities.