• School Mathematics
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• v.1 no.1
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• pp.7-17
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• 1999

The purpose of this note is to give insights into the role of parallelism to the middle school mathematics. According to NCTM(1998), the middle grades mathematics classroom should be a place in which students regularly engage in thoughtful activity that relates to their emerging capabilities of finding and imposing structure, conjecturing and verifying, and engaging in abstraction and generalization. In this aspect it is desirable to reinvestigate Euclidean Parallel Postulate in the axiomatic point of view in the level of the middle school mathematics. Reconstructing the contents Greenberg(1993), and we explain the statements which are logically equivalent to the Parallel Postulate for mathematics teachers in the middle school.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.1
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• pp.37-62
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• 2014

In this thesis, we inquire into teaching method of decimal fraction concept in elementary mathematics education based on measurement activity. For this purpose, our research tasks are as follows: First, we design a experimental learning-teaching plan of 'decimal fraction' unit in 4th grade textbook and verify its effect. Second, after teaching experiment using experimental learning-teaching plan, we analyze the student's status of understanding about decimal fraction concept. As stated above, we have performed teaching experiment which is ruled by new lesson design and analysed the effects of teaching experiment. Through this study, we obtained the following results. First, introduction of decimal fraction based on measurement activity promotes student's understanding of measuring number and decimal notation. Second, operator concept of decimal fraction is widely used in daily life. Its usage is suitable for elementary mathematics education within the decimal notation system. Third, a teaching method of times concepts using place value expansion of decimal fraction is more meaningful and has less possibility of misunderstanding than mechanical shift of decimal point. Fourth, teaching decimal fraction through the decimal expansion helps students with understanding of digit 0 contained in decimal fraction, comparing of size and place value. Fifth, students have difficulties in understanding conversion process of decimal fraction into decimal notation system using measurement activity. It can be done easily when fraction is used. However, that is breach to curriculum. It is necessary to succeed research for this.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.1
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• pp.123-134
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• 2010

Recently, mathematics education have been emphasized on developing students' mathematical thinking and problem solving abilities. Accordance with this emphasis, dramatical changes are needed in learning mathematics not merely let alone students solve real-made mathematics problems. The project learning to explore a counterweight activity will have an effects on positive mathematical attitude(to pose problem, to have curiosity) and mathematical thinking(power 10-digit representation, 2-digit number, two representation of 3-digit number, connect exponential number and log situation) which could develop understanding problems and critical thinking.

• Journal of Elementary Mathematics Education in Korea
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• v.8 no.1
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• pp.45-61
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• 2004

The seventh curriculum of mathematics which value much of the learners' participative activities became conspicuous by introducing a new system of ‘activities’ to the textbook in particular, Then I categorized and analyzed the ‘activities’ proposed in actual textbooks in the context of specific operative activities. The objective of this study is for understanding the features and trends of the activities proposed in textbooks.

• Journal of the Korean School Mathematics Society
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• v.9 no.2
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• pp.209-227
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• 2006

From this research, we want to get results that have interested the difference from character of students with the motivation of the learning, confidence and habit through the activity oriented class. When teacher teach students of the learning disability with participant class and activity class, they have encouraged and have positive disposition about mathematics. Therefore teachers should try to give chance doing in mathematics class to students with learning disability.

• Communications of Mathematical Education
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• v.35 no.2
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• pp.193-212
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• 2021

This study is to support the school's mathematics exploration activities. Mathematics exploration is a very important mathematical activity not only for mathematics teachers, but also for students. Looking at the development of mathematics, it has been extended from one mathematical fact to a new mathematical fact. Mathematics exploration activities are not unique to mathematicians, and opportunities are equally given to all ordinary people who are learning mathematics and teaching mathematics. Therefore, the purpose of this study is to develop a method of mathematics exploration activities that teachers and students can perform in schools, based on mathematics exploration activities based on one mathematical fact. Specifically, the cosine law was selected as one mathematical fact, and mathematical exploration activities were performed based on the cosine law. By analyzing the results of these mathematics exploration activities, we developed a method to explore school mathematics. Through the results of this study, it is expected that mathematics exploration activities will be conducted equally by students and teachers in the mathematics classroom.

• Natural Product Sciences
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• v.23 no.4
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• pp.291-298
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• 2017

Six dammarane-type triterpenoids, dammar-24-en-$3{\beta}$-ol (1), $3{\beta}$-epicabraleahydroxy lactone (2), (E)-25-hydroperoxydammar-23-en-$3{\beta}$,20-diol (3), dammar-24-en-$3{\beta}$,20-diol (4), $3{\beta}$-acetyl-20S,24S-epoxy-25-hydroxydammarane (5), and $3{\beta}$-epiocotillol (6) were isolated from the methanolic extract of the bark of Aglaia elliptica. The chemical structure were identified on the basis of spectroscopic evidence and by comparison with those spectra previously reported. Compounds 1 - 6 were isolated first time from this plant. Compounds 1 - 6, along with a known synthetic analog, cabraleone (7) were evaluated their cytotoxic activity against P-388 murine leukimia cells in vitro. Among those compounds $3{\beta}$-acetyl-20S,24S-epoxy-25-hydroxydammarane (5) showed strongest cytotoxic activity with $IC_{50}$ value of $8.02{\pm}0.06{\mu}M$.

• Education of Primary School Mathematics
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• v.5 no.1
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• pp.13-20
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• 2001

Interaction through communication plays critical role in the mathematics learning in the sociocultural perspectives. The communication make the students construct shared knowledge, and also plays a role of mediation in making meaning. So, we have to consider sociocultural eprspectives in design of the mathematics leaning using computer. While Computer Assisted Instruction was the one-directional teaching program which proceed from computer to students, mathematics leaning using computer in the sociocultural perspectives have to consider two-directional instruction that proceed from computer to students as well as from students to computer. This interactional activity is the critical thing in the mathematics learning using computer.

• The Mathematical Education
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• v.43 no.4
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• pp.405-417
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• 2004

This study is on the use of mathematics program for School Mathematics Education. According to the ‘technology principle’ by NCTM and teaching-learning methods by the 7th curriculum, we developed mathematics learning activities with mathematics program. This activity is to construct designs with graphs by using mathematics program(GrafEq.). In this study, we practiced these learning activities with pre-service mathematics teachers. The mathematics educational effects of these learning activities in this study are analyzed as follows; active & spontaneous search for mathematical knowledge, the experience of problem solving, affirmative view-point of mathematics, understanding of practical use of mathematics, acquisition an interest & motivation of learning mathematics etc. When students learn graphs of function, the concept of inequality in secondary school mathematics class., mathematics teachers can make a good use of constructing designs by mathematics program(GrafEq.). This will help to practice of teaching-learning methods by the 7th curriculum.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.81-109
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• 1999

This study aims to reflect the basic principles and teaching-teaming principles of Realistic Mathematics Education in order to suppose an way in which mathematics as an activity is carried out in primary school. The development of what is known as RME started almost thirty years ago. It is founded by Freudenthal and his colleagues at the former IOWO. Freudenthal stressed the idea of matheamatics as a human activity. According to him, the key principles of RME are as follows: guided reinvention and progressive mathematisation, level theory, and didactical phenomenology. This means that children have guided opportunities to reinvent mathematics by doing it and so the focal point should not be on mathematics as a closed system but on the process of mathematisation. There are different levels in learning process. One should let children make the transition from one level to the next level in the progress of mathematisation in realistic contexts. Here, contexts means that domain of reality, which in some particular learning process is disclosed to the learner in order to be mathematised. And the word of 'realistic' is related not just with the real world, but is related to the emphasis that RME puts on offering the students problem situations which they can imagine. Under the background of these principles, RME supposes the following five instruction principles: phenomenological exploration, bridging by vertical instruments, pupils' own constructions and productions, interactivity, and interwining of learning strands. In order to reflect how to realize these principles in practice, the teaming process of algorithms is illustrated. In this process, children follow a learning route that takes its inspiration from the history of mathematics or from their own informal knowledge and strategies. Considering long division, the first levee is associated with real-life activities such as sharing sweets among children. Here, children use their own strategies to solve context problems. The second level is entered when the same sweet problems is presented and a model of the situation is created. Then it is focused on finding shortcomings. Finally, the schema of division becomes a subject of investigation. Comparing realistic mathematics education with constructivistic mathematics education, there interaction, reflective thinking, conflict situation are many similarities but there are alsodifferences. They share the characteristics such as mathematics as a human activity, active learner, etc. But in RME, it is focused on the delicate balance between the spontaneity of children and the authority of teachers, and the development of long-term loaming process which is structured but flexible. In this respect two forms of mathematics education are different. Here, we learn how to develop mathematics curriculum that respects the theory of children on reality and at the same time the theory of mathematics experts. In order to connect the informal mathematics of children and formal mathematics, we need more teachers as researchers and more researchers as observers who try to find the mathematical informal notions of children and anticipate routes of children's learning through thought-experiment continuously.