Abstract: Nine experiments with similar procedures to test children's conceptionof cardinal and ordinal numbers and their ability in addition-substractionoperations have been carried out in nine districts throughout China. A totalof 780 aged 3-7 yrs has been tested and 9 experimental results have beenreported. This paper is a general summary of these nine reports. Based on thedata obtained the following problems are disccussed: a) the development ofthe child's counting ability; b) the development of the child's conception ofgroup and addition-substraction operations; c) the development of the child'sconception of seriation and the relationship between cardinal and ordinalnumbers; d) the child's conservation of number; e) the development of thechild's mathematical reasoning; f) the part different cognitive processesplay in the child's conception of number; g) the stages and turning pointsin the development of the child's conception of number; h) the role ofcultnral background in develoing thechild's conception of number and oper-ational ability and; i) the interrelation between different stages or aspectsin the development of the child's conception of number and operationalability. This study, as the authors point out, is still in its prelimilary stage.However, quite an amount of scientific data has been obtained and someproblems for further investig ation have been derived. Even more impor-tant, the authors have gained some experience in this form of cooperativeresearch, which will be useful in our future work.

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