Abstract: This is a comprehensive report of the findings from studies of 959 7-12yearsold child subjects from 10 districts throught China. The developmentof recognition of numbers (including transfer between figure and number),ordinals and sets of series, composition and decomposition of numbers, operationand application was explored. And on the basis of the findings the authorsdiscussed the relations between knowledge learning and development of arit-hmetical concepts, the process of this development, the environmental effects,and stages of the development.The cooperative way which they have adoptedfor several years is also remarked.

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