• School Mathematics
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• v.7 no.4
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• pp.319-336
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• 2005

This study is to find the properties of Diffy activity and to investigate the problems and conjectures which could be posed in the Diffy activity. The Diffy is a simple subtracting activity. But, 1 think it is a field where the mathematical thinking can take place. I proposed some problems and conjectures which can be posed. I solved the problems using excel and the software I developed and proposed the related data. I think such problems and the data will be the good materials for elementary students and gifted to think mathematically with.

• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.491-510
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• 2017

This study analyzes on conjecturing tasks in elementary mathematics textbook. We adopted Peircean semiotic perspective and variation theory to analyze conjecturing tasks in elementary mathematics textbook. We specifically analyzed mathematical tasks designed to support students' inquiries into definitions and properties of quardrilaterals. As a result, we found that conjecturing tasks in textbooks do not focus on supporting students' diagrammatic reasoning and inductive verification on provisional abductions. These tasks were mainly designed to support students' conjecturing on commonalities of mathematical objects rather than differences between objects.

• Journal for History of Mathematics
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• v.17 no.3
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• pp.13-22
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• 2004

In this paper, we consider two conjectures, the Bieberbach Conjecture that was proved true and the Lu Qi-Keng Conjecture that was proved not true. We inspect them historically and introduce the interesting results. From them we find that the deep theory of mathematics comes from continuous conjectures.

• Journal of Educational Research in Mathematics
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• v.23 no.4
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• pp.553-565
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• 2013

The purpose of this study was to examine how the Lakatos method works in the elementary teacher education program. Elementary preservice teachers were given a task in which they examined the Pick's theorem. The finding revealed that Lakatos method was usable in the elementary teacher education. They produced initial conjecture and found counterexamples, and finally made improved conjectures. These experience encourage them to change their belief of teaching and learning mathematics and to find alternative ways of teaching mathematics.

• Communications of Mathematical Education
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• v.12
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• pp.185-200
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• 2001

증명은 수학에서 기초적이고도 중요한 주제이다. 추측을 만들어내고 자신에게는 물론 타인에게까지 그 추측을 정리로서 확신시키는 활동은 수학활동에서의 핵심이라고 할 수 있다. 그러나 현재의 증명 학습지도에서는 학생들의 수준보다는 높은 증명 발달단계를 제시하고 있다는 보고와 함께 기존의 지도방법의 개선책을 요구하고 있다. 따라서 본고에서는 몇 가지 증명의 발달 단계를 정리해 보고 Balacheff의 증명 4단계를 토대로 하여 증명활동을 점진적인 구성으로 제시한다.

• School Mathematics
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• v.13 no.1
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• pp.107-125
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• 2011

In this paper, we investigated how the GSP environments impact students' conjecturing of geometric properties. And we wanted to draw some implication in teaching and learning geometry in dynamic geometric environments. As results, we conclude that when students were given the problem situations which almost has no condition, they were not successful, and rather when the problem situations had appropriate conditions students were able to generate many conditions which were not given in the original problem situations, and consequently they were more successful in conjecturing geometric properties. And the geometric properties conjectured in GSP environments are more complex and difficult to prove than those in paper and pencil environments. Also the function of moving screen with 'Alt' key is frequently used in conjecturing geometric properties with functions of measurement and calculation of GSP. And students felt happier when they discovered geometric properties than when they could prove geometric properties.

• Journal for History of Mathematics
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• v.21 no.3
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• pp.113-126
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• 2008

This work is devoted to study about the abc conjecture: how it works in the development of the proof of Fermat's last theorem and more generally in the diophantine equation theory. And it is also studied the application of the abc conjecture to the iteration of polynomials.

• Education of Primary School Mathematics
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• v.16 no.1
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• pp.21-33
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• 2013

In this study, We analyzed the mathematical thinking of sixth grade students showed mathematics lessons through the application of Lakatos' methodology and search for the role of their teachers in this lessons. We supposed to find the solution to the way of teaching-learning regarding the Lakatos' methodology for the elementary school level. According to the stages of presenting a problem situation, suggesting an initial conjecture, examining the conjecture, and improving the conjecture, we had lessons 8 times that are applied to Lakato's methodology. We gathered and analyzed data from lessons and interviews recording videotapes, documents for this study. The participants showed a lot of mathematical thinking. They understood the problem situation with the skill of fundamental thinking and suggested the initial conjecture by the skill of developmental thinking and they found a counter-example to be able to rebut the initial conjecture by critical thinking. Correcting the conjecture not to have counter-example, they drew developmental thinking and made their thinking generalize.

• Communications of Mathematical Education
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• v.8
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• pp.17-32
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• 1999

본 논문의 목적은 Cabri II 를 이용하여 형식적이고 연역적인 증명수업 방법의 대안을 찾는 데 있다. 형식적인 증명을 하기 전에 탐구와 추측을 통한 발견과 그 결과에 대한 비형식적인 증명 활동을 강조한다. 역동적인 기하소프트웨어인 Cabri II 는 작도가 편리하고 다양한 예를 제공하여 추측과 탐구 그리고 그 결과의 확인을 위한 풍부한 환경을 제공할 수 있으며, 끌기 기능을 이용한 삼각형의 변화과정에서 관찰할 수 있는 불변의 성질이 형식적인 증명에 중요한 역할을 한다. 또한 도형에 기호를 붙이는 활동은 형식적인 증명을 어렵게 만드는 요인 중의 하나인 명제나 정리의 기호적 표현을 보다 자연스럽게 할 수 있게 해 준다. 그러나, 학생들이 증명은 더 이상 필요 없으며, 실험을 통한 확인만으로도 추측의 정당성을 보장받을 수 있다는 그릇된 ·인식을 심어줄 수도 있다. 따라서 모든 경우에 성립하는 지를 실험과 실측으로 확인할 수는 없다는 점을 강조하여 학생들에게 형식적인 증명의 중요성과 필요성을 인식시킬 필요가 있다. 본 연구에 대한 다음과 같은 후속연구가 필요하다. 첫째, Cabri II 를 이용한 증명 수업이 학생들의 증명 수행 능력 또는 증명에 대한 이해에 어떤 영향을 끼치는지 특히, van Hiele의 기하학습 수준이론에 어떻게 작용하는 지를 연구할 필요가 있다. 둘째, 본 연구에서 제시한 Cabri II 를 이용한 증명 교수학습 방법에 대한 구체적인 사례연구가 요구되며, 특히 탐구, 추측을 통한 비형식적인 중명에서 형식적 증명으로의 전이 과정에서 나타날 수 있는 학생들의 반응에 대한 조사연구가 필요하다.

• Education of Primary School Mathematics
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• v.26 no.4
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• pp.257-275
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• 2023

In this study, we designed and implemented a instruction emphasizing mathematical argument for fifth-grade students and analyzed the teaching practices. Through a literature review related to instruction emphasizing mathematical argument, we organized a teaching model of five phases that explain why the general claim that the sum of consecutive odd numbers equals a square number is true: 1) noticing patterns, 2) articulating conjectures, 3) representing through visual model, 4) arguing based on representation, 5) comparing and contrasting. Then, we analyzed the argumentation stream by phases to observe how the instruction emphasizing mathematical argument is implemented in the elementary classroom. Based on the results of this study, we discuss the implications of teaching a mathematical argument in elementary school.