抄録
This study examined an effective teaching method to teach generalized and various solution methods for finding the sum of the internal angles of a polygon to fifth graders in elementary school mathematics. Two lesson plans, which were different in the phase of scaffolding, were developed. In experimental class, a figure that presents one method to find the sum of the internal angles of quadrilateral was given as scaffolding, and all the class discussed the solution method, and then tried to find another solution method. In the control class, they were directed to find different solution methods without scaffolding. The following points were found from the result of the post-test. First, the teaching method used in this study for teaching generalized solution methods was effective. Second, the teaching method used in the experimental class for teaching various solution methods was more effective than that of the control class. This means that the guided discovery method is more effective than non-guided discovery method.
