In this video below, Mrs. Kathrine Fraleigh, presents a Cards and Counters lesson to one of her students. This Montessori lesson is a set of numerals 1-10 and plastic discs. The layout of the counters is what makes the counting work different. The student lays out the numerals, and then lays the discs out in pairs under the numbers.
This will reinforces the knowledge that each number is made up of separate quantities. The student will master the sequence of numbers and how many separate units from each number.
Montessori took the idea that the human has a mathematical mind from the French philosopher Pascal. Maria Montessori said that a mathematical mind was “a sort of mind which is built up with exactity.” The mathematical mind tends to estimate, needs to quantify, to see identity, similarity, difference, and patterns, to make order and sequence and to control error.
The child gets sensorial impressions of the mathematical concepts and movement supports the learning experience. The material begins with concrete experiences but moves the child towards the abstract. There is also a progression of difficulty. In the presentation of the material, a pattern is followed.