Number processing and mental calculation in school children aged 7 to 10 years: a transcultural comparison.

Neuropsychological studies of dyscalculic patients show that arithmetical development is not a unidimensional process. In transcultural investigations, cultural, educational and linguistic factors might affect differently the various components of mathematical development. Four hundred and sixty schoolchildren aged 7 to 10 years from Brasilia, Brazil (n = 141), Paris, France (n = 160) and Zurich, Switzerland (n = 159) were asked to perform eleven number processing and calculation tasks. Chronological age, which was almost confounded in this study to educational level, had a strong effect on some tasks (knowledge of the written code of numbers, number comparison, mental calculation, problem solving), but only a slight effect on other tasks (counting dots, counting backwards, estimation). Also, linguistic factors and factors related to the socio-economic level of the family had different effects on the various components of calculation and number processing. Evidence from developmental studies has to be integrated into theoretical models of calculation and number processsing, which are presently based mainly on results from neuropsychological studies of dyscalculic patients.