This system of education was developed in the early part of the last century by Dr.Maria Montessori, initially for 3 to 6 year olds, and gradually for higher age groups.
Broadly speaking, the Montessori System believes that a child's education should be guided by his inner needs and interests.
Keeping this in mind, the system evolved a process which catered to the differing needs of different age groups. 3-6 year olds need to touch and feel. Whereas 6-12 year olds need to use their legs and work in groups.
Abacus makes extensive use of the learning materials of the Montessori method, but also draws the methodology from the work done in the field of education over the years.