The beauty of the Montessori classroom comes through strongly because of the inclusion of multiple ages in one environment. Classrooms have an age span of three to four years. This creates a community of students who posses beginning, developing, and proficient skills of all concepts being taught. Because of the social nature of children, they naturally want to share their insights and experiences with each other. When allowed to share work time together, children impart knowledge to each other in a way that adults cannot. This is because the relationships, mode of teaching, and conversations are among peers.
Children are grouped in mixed ages and abilities in three year age spans; Toddler 18 months-3 years, Primary 3-6 years, Lower Elementary 6-9 years, Upper Elementary 9-10 years and Middle School 10-13 years. By fostering learning in a multi-age classroom, children are empowered to teach and guide each other, learn collaboratively, and work to their particular abilities and interest levels.
The child’s progress does not depend only on his age, but also on being free to look about him. Our schools are alive. To understand what the older ones are doing fills the little ones with enthusiasm. The older ones will be happy to teach what they know.
Maria Montessori, The Absorbent Mind, p. 207