David Friedman:

One point I should have made at the beginning of the previous post is the distinction between unschooling and homeschooling. Most home schooling is not unschooling–the parents have a curriculum and are following something closer to the conventional model than we are. And one can do unschooling in a school. Our kids were in a very small private school modeled on Sudbury Valley School for some years. Eventually problems arose, we switched from school unschooling to home unschooling, and on the whole found it more satisfactory. Hence the titles of these posts.
When our daughter was five, she was going to a local Montessori school. Her mother thought she was ready to learn to read; they didn’t. So Betty taught her to read, using Doctor Seuss books. Our son, three years younger, observed the process and taught himself. We heard about the local Sudbury school, new that year, brought our daughter over to visit. She decided she preferred it to the Montessori school, so we shifted her. A few years later we added her brother, a few years after that shifted to home schooling.
The Sudbury model includes classes if students want them. When our daughter was about ten there was a class, lasting somewhat over a year, in math. It started assuming the students knew nothing, ended with the early stages of algebra. That is pretty much all of the formal instruction either of them had. In addition, we required them to learn the multiplication tables, which are useful to know but boring to learn. That, I think, was the closest thing to compulsory learning in their education.