抄録
The author thinks Kamii's theory and practices give useful suggestions to improve on "conveying knowledge" type teaching and to promote a class which children create, for they have characters as follows: (i) to set the most important goal of education is "autonomy". (ii) to practice constructive teaching method ("a method of teaching that guide without instruction"). (iii) to use situations in daily living, game, discussion in classroom activities and to regard children own making sense as important. Then, the purposes of this paper are follows: 1. to examine Kamii's practices and opinion that "the teaching of algorithms in the primary grade is harmful". 2. to carry out a class based on such Kamii's opinion, and to consider suggestions on Japanese arithmetic education from the results of the class. Kamii states from her practices that the teaching of algorithms in the primary grades is harmful for the following reasons: 1. Algorithms force children to give up thier own numerical thinking. 2. They "unteach" place value and hinder children's development of number sense. 3. They make children development on the spatial arrangement of digits (or paper and pencil) and on other people. So based on such Kamii's opinion, now the author sets up research task as below, and practice a class (2hours) of two-digit-numbers addition by writing form to first-grade-pupils. [research task] When children are encouraged to do problem their own procedurs, how they construct (invent) way of two-digit-numbers addition by writing form through discussion. In this class, the numbers of pupils which support the way of calculating from the number of tens changes as follows. ・latter half of the first hour (24+13)……28/39 → ・first half of the second hour (18+13)……11/39 → ・last of the second hour (18+13)…………5/39 So, we get a result different from the result which Kamii was got, i.e. "When children are not taught any algorithms and are, insread, encouraged to invent their own procedures, their thinking goes in a different direction from the algorithms they are taught". But the result give various suggestions to introduce Kamii's theory and practice into Japanese arithmetic education more effectively.
