• The Mathematical Education
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• v.38 no.2
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• pp.179-187
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• 1999

Math teachers are very short of computer tools and manipulatives to use in geometry classes of middle schools for the development of spatial abilities. At most they can ask student to make regular polyhedrons for helping the students to understand by concrete experience, but this experience is not enough to develop spatial abilities in spatial figures including the regular polyhedrons. This article is to introduce instructional materials for development of spatical ability in the regular polyhedrons using computer software, Geometer's Sketchpad. In this article, students can imagine the whole figure through the parts of a plane figure and think of the parts from the solid figure by free movement from 2 dimensions to 3 dimensions, or from 3 dimensions to 2 dimensions. Also, the instructional materials devised in this article will be good to enhance spatial abilities because the relation of 1-1 correspondence in the movement of the parts can be conserved and observed precisely, which is very hard to demonstrate and visualize by paper-and-pencil. It is recommended that this kind of materials should be developed in various ways for teachers to use them directly in their geometry classes.

• Journal of Gifted/Talented Education
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• v.18 no.1
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• pp.53-77
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• 2008

This study was conducted with the focus on the process of constructing 3 definition and produced definitions as well as gifted students' conceptions of a mathematical definition In the study, the students made five types of regular polyhedrons (section1), observed them and stated their characteristics (section2) and then constructed a definition of regular polyhedrons based on their observations (section3). We divided students into two groups by analyzing students' definitions. One group made definitions that were consist with a mathematical definition of regular polyhedrons, the other one made definitions that were not. We checked if they fulfilled requirements for a mathematical definition. Researchers sought to gain various suggestions through the analysis of the observations and definition laid down by the students and through the characteristics shown by the students in the process of defining the concept.

• Journal of Elementary Mathematics Education in Korea
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• v.17 no.2
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• pp.351-370
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• 2013

The purpose of this study is to analyze the modes of visualization which appears in the process of thinking that mathematically gifted 6th grade students get to understand components of the three-dimensional shapes on the duality of regular polyhedrons, find the duality relation between the relations of such components, and further explore on whether such duality relation comes into existence in other regular polyhedrons. The results identified in this study are as follows: First, as components required for the process of exploring the duality relation of polyhedrons, there exist primary elements such as the number of faces, the number of vertexes, and the number of edges, and secondary elements such as the number of vertexes gathered at the same face and the number of faces gathered at the same vertex. Second, when exploring the duality relation of regular polyhedrons, mathematically gifted students solved the problems by using various modes of spatial visualization. They tried mainly to use visual distinction, dimension conversion, figure-background perception, position perception, ability to create a new thing, pattern transformation, and rearrangement. In this study, by investigating students' reactions which can appear in the process of exploring geometry problems and analyzing such reactions in conjunction with modes of visualization, modes of spatial visualization which are frequently used by a majority of students have been investigated and reactions relating to spatial visualization that a few students creatively used have been examined. Through such various reactions, the students' thinking in exploring three dimensional shapes could be understood.