Montessori classrooms are multi-aged by genius design. Children shouldn’t be bound by traditional age or grade levels.
Most families have children of different ages. Likewise, most work environments have different-aged employees working together. That is why Dr. Montessori felt that the “industrial model” of same-age, same-grade classrooms was unnatural.
At the same time, she saw that children went through natural developmental states in approximately three-year cycles. Through her observation, as well as observations by Montessori teachers and child development experts, the placement of children in three-year cycles was found to be the optimum way to group children in Montessori schools.
Mixed-age groups also contribute to the moral development of the child, as students are taught to respect others, be sensitive to their different needs, and to collaborate in a helpful spirit. Children are helpful and cooperative by nature, and the Montessori environment supports and encourages that wonderful aspect of every child’s personality.