While I do agree that children learn by engaging exercises, I totally disagree with the unschooling and Montessori methods of education.
Unschooling, as the term states refers to an unstructured way of educating children. Children learn what is relevant for the day without retaining significant knowledge. The Montessori program is child-led, and while the educational setting is generally aesthetically pleasing, the educational results are mixed.
Reading, writing, and mathematics should be taught daily and in a specific format, especially in the earlier years. Unschooling does a disservice to children, and I feel this method should be avoided.
Many children come out of Montessori programs and have difficulty adjusting to a standard school format. A strong educational foundation is necessary for future academic success.