Abstract
This paper concerned first the present definition of "Number Conversion Skills" as the ability of a child to convert concrete materials or numerical signs into abstraction, and to be able to express such figures. We examined developmentally the role of numerals in the process by which children acquire such Number Conversion Skills. Task materials were of four types : concrete objects, number cards, numerals (e.g., to name sets of objects and to point same named number cards) and numbers (e.g., to read digits and to point digits as written names of sets). Participants were 335 children (age range=45-82 months) at two Japanese preschools. The main results included the following : (1) Conversion into numerals was achieved at the earliest ages, while the ability to convert into number cards was acquired last. (2) It was suggested that numerals serve a pivotal role in the Number Conversion acquisition process, as a transition between concrete objects and numbers or number cards. In summary, the first stage in the acquisition of Number Conversion Skills appears to be marked by the use of numerals.
