Refers to the teaching organization form in which a teacher teaches more than two students of different grades in the same classroom. The teacher skillfully arranged the activities of several age groups or classes in one class at the same time.

Applicable: In areas with few students, few teachers and poor teaching facilities, education in rural and mountainous areas is mainly popularized.

Insufficient: teachers have less time to directly guide students; There are many mutual interferences; Teachers have a heavy workload.