Abstract: This is a comprehensive report of 9 experiments we did during the pastthree years. From our previous 4 experiments, we put forword 12 criteria forthe comprehension of part-whole relationship. The same 12 criteria were usedin the 3 experiments (integers, geometrical figures and fraction) designed toinvestigate the reaction of children to part-whole relationship, after which 2teaching experiments were carried out to apply and check the results obtained.On thebasis of the results of these 9 experiments, the authors discussed howthe understanding of the intrinsic nature of the objects to be known (numberand arithmetical concepts in these studies) facilitates the knowing processes ofthe knower, the age characteristics, developmental levels and periods of acceler-ated growth during the process of comprehension of part-whole relationship.That the children's cognition of part-whole relationship may be effectively ap-plied to the learning of arithmetic was also discussed.

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