Want to keep in the classroom with students, not much and not too little. Because if the students will lack new ideas. It is quiet and not too much fun, but if you are a teacher for each class will be taught to.
To keep the number of students in the classroom is not much and not too little. If a student is not a new idea. The room was quiet and not a lot of fun, but if the teacher does not have to teach each subject thoroughly.
Want in the classroom the students very much, and not too much. Because if a student at least to lack new ideas The room is quiet and having fun, but if too much teacher each subject will teach not thoroughly.