In Montessori the children work with manipulatives designed to give them a concrete idea of the concept being taught. Once they have abstracted that idea they leave the manipulative behind. In contrast, public/parochial schools mostly use textbooks and workbooks to teach concepts.
But in Montessori, the paperwork usually comes after the concept has been understood.
The Story of Numbers is the fifth in the series of five Great Lessons in the Montessori Elementary curriculum.