School
Pedagogy is the science of teaching children. Different schools use different ways of teaching. There is quite a lot of disagreement about what and how students should be taught. Many countries solve this by allowing different types of school, so parents and children have some choice. Choices may include home education, which is a controversial idea. Few people do this. Even in pre-modern times most children were taught in groups. Age-grouping is also ancient. It was done in many African tribes for a long time before the present.