Magical Grades

It has been a question to us why is it we received a grade of "2.6" meanwhile the teacher has no basis for giving such. It is doubtful in our part to have such grade where in fact the teacher don't have classes on us. Another thing is that our teacher is not holding exams or what so ever activities to classify our standing in class. It's shameful on his part for the students are calling it as "Magical Grades!"