Ah yes.. Class 3-E. Otherwise known as the Assassination Classroom of Kunugigaoka Junior High School, the class of outcasts.

Korosensei sat at his desk, preparing for his lesson and his upcoming test questions. Despite having Mach 20 speed, it takes him a bit longer to create these tests and exams, since the questions he writes down are different for every student. He takes in account of what a student is good and bad at, and makes sure to focus the topics on those areas for improvement.