It gave more time for review. I believe I got more out of my students because I had that extra time to spend with them. Small class size allowed me to deal more directly with discipline problems. It is a key factor in having fewer students be retained. Students receive more individual attention.
Smaller classes are friendlier and more intimate.
There are fewer discipline problems in the classroom. Students are more likely to participate in activities. The atmosphere is more conducive to the use of manipulatives, which enhances learning. More in depth study of subject matter is possible. Small class size should be a requirement for all primary grades.