Nineteenth century school houses had all the grades from kindergarten on up through the eighth grade (high school was optional) housed under one roof. The primer (kindergarten) kids sat in the front while the older students sat in the back. Somehow, one teacher was able to teach all these different kids from different books under one roof. I realize there are many more people nowadays and that makes small school houses impractical, but maybe there's something to be said for mixing different ages together. Let the older children help the younger ones with their studies, which will teach the older children responsibility and empathy, and the younger children can also learn proper behavior from the older ones.