The purpose of the study was to investigate the reality of middle school mathematics teachers' subject matter knowledge for teaching mathematical conjecture and justification. Data in the study were collected through interviewing nine Chinese and ten Korean middle school mathematics teachers. The teachers responded to the question that was designed in the form of a scenario that presents a teaching task related to a geometrical topic. The teachers' oral responses were audiotaped and transcribed, and their written notes were collected. The results of the study were compared to the analysis of American and Chinese elementary and secondary teachers' responses to the same task in Ball (1988) and Ma (1999). The findings of the study suggested that teachers' approaches to explaining and demonstrating a mathematical topic were significantly influenced by their knowledge of learners and knowledge of the curriculum they teach. One of the practical implications of the study is that teachers should recognize the advantages of learning the conceptual structure of a mathematical topic. It allows the teachers to have the flexibility to come up with meaningful mathematical approaches to teaching the topic, which are comprehensible to the learners whatever the grade levels they teach, rather than rule-based algorithms.

In this paper we study activity theory and Davydov's learning activity theory. We analyze brief history of activity theory in Russia, structure of human activity, and Davydov's studies in activity theory. Especially we analyze Davydov's 1st grade mathematics textbook, and try to investigate embodiment of Davydov's learning activity theory in his mathematics textbook.

The purpose of this study is to analyze whether mathematics education course can improve secondary pre-service math teacher' belief and correlation on pre-service math teacher' belief and mathematics education achievement. In order to achieve this purpose, the test was conducted to the subject of 34 pre-service secondary math teachers of the grade 2 and grade 4 who were chosen from H university in D city and we analyzed the results. Findings on this study are as follows. First, there was meaningful difference in the pre-service math teacher' belief with significant level of 0.05. This proved that mathematics education course was effective on improving pre-service math teacher' belief. Second, there was not meaningful correlation in the pre-service math teacher' belief and mathematics education achievement.

Addition problems can be divided into the 'problem of quantity' which does not have the concept of object or unit, and the 'problem of number' which have the concept of object or unit. 'Additive property' is the factor which has to be considered in the former case. On the other hand, 'additive property' is not considered and meaningless in the latter case. However, this additive property is not emphasized in the elementary curriculum that mostly deals with quantitative problems, so related errors are occurred in actual life. In this study, we will investigate to the pre-service elementary teachers through the problems of deciding the additive property. The result shows that the pre-service elementary teachers' cognition of additive problems is insufficient. This study will provide focal points in the teacher education and the elementary education, and the clues for the operating programs through the information about the tendency of errors.

This research is a study on student's understanding fundamental concepts of mathematical curriculum, especially in geometry domain. The goal of researching is to analyze student's concepts about that domain and get the mathematical teaching methods. We developed various questions of descriptive assessment. Then we set up the term, procedure of research for the understanding student's knowledge of geometric figures. And we analyze the student's understanding extent through investigating questions of descriptive assessment. In this research, we concluded that most of students are having difficulty with defining the fundamental concepts of mathematics, especially in geometry. Almost all the students defined the fundamental conceptions of mathematics obscurely and sometimes even missed indispensable properties. And they can't distinguish between concept definition and concept image. Prior to this study, we couldn't identify this problem. Here are some suggestions. First, take time to reflect on your previous mathematics method. And then compile some well-selected questions of descriptive assessment that tell us more about student's understanding in geometric concepts.

In this paper, we investigate the contents of Rule of Excess and Deficit in the second volume of San Hak Jeong Ui (Arithmetic Definition) compiled by Nam Byong Kil and corrcted by Lee Sang Hyok in the Choson Dynasty period.(Emperor Ko Jong, 1867).