• Journal of the Korean School Mathematics Society
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• v.10 no.2
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• pp.237-246
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• 2007

According to 7-th curriculum, irrational number should be introduced using non-repeating infinite decimals. A rational number is defined by a number determined by the ratio of some integer p to some non-zero integer q in 7-th grade. In 8-th grade, A number is rational number if and only if it can be expressed as finite decimal or repeating decimal. A irrational number is defined by non-repeating infinite decimal in 9-th grade. There are misconceptions about a non-repeating infinite decimal. Although 1.4532954$\cdots$ is neither a rational number nor a irrational number, many high school students determine 1.4532954$\cdots$ is a irrational number and 0.101001001$\cdots$ is a rational number. The cause of misconceptions is the definition of a irrational number defined by non-repeating infinite decimals. It is a cause of misconception about a irrational number that a irrational number is defined by a non-repeating infinite decimals and the method of using symbol dots in infinite decimal is not defined in text books.

• Journal of the Korean Society for information Management
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• v.31 no.3
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• pp.7-27
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• 2014

Constructions and Architecture fields were divided into Architecture engineering and Architecture in the 5th edition of Korean Decimal Classification (KDC), but those were combined in the 6th edition of KDC published in 2013. The purposes of this study are to find problems and to suggest modifications through comparing and analyzing the 5th and the 6th editions of KDC, Dewey Decimal Classification, Nippon Decimal Classification and Universal Decimal Classification. The necessity of reclassification, a long classification number for History of Architecture and addition of categories of traditional building and architectural engineering are required to improve the 6th edition of KDC and the improvements and modifications of those problems are suggested.

• The Mathematical Education
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• v.45 no.3 s.114
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• pp.275-293
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• 2006

The purpose of this study was to analyze the connection between students' errors and prior knowledge as an attempt to design an efficient teaching method in decimal computation. A survey on decimal computations was conducted in two 6th grade elementary school classrooms. Error patterns on decimal computations were analyzed and clinical interviews were conducted with 8 students according to their error patterns. Main errors resulted from the insufficient understanding of prior knowledge such as place value, connection between decimals and fractions, meaning of operations, and computation principles of fractions. In order to help students overcome such obstacles, a teaching experiment was designed in a manner that strengthens a profound understanding of prior knowledge related to decimal computations, and connects such knowledge to actual decimal calculations. This study showed that well-designed lesson plans with base-ten blocks might decrease students' errors by helping them understand decimals and connect their prior knowledge to decimal operations.

• School Mathematics
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• v.19 no.1
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• pp.209-228
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• 2017

Understanding decimal numbers is important in mathematics as well as real-life contexts. However, lots of students focus on procedures or algorithms of decimal numbers without understanding its meanings. This study analyzed teaching method related to decimal numbers in a series of mathematics textbooks of Korea, Japan, Singapore and the US. The results showed that three countries except Japan introduced the decimal numbers as another name of fraction, which highlights the relation between the concept of decimal numbers and fractions. And limited meanings of decimal numbers were shown such as 'equal parts of a whole' and 'measurement'. Especially in the korean textbooks, relationships between the decimals were dealt instrumentally and small number of models such as number lines or $10{\times}10$ grids were used repeatedly. Based these results, this study provides implications on what and how to deal with decimal numbers in teaching and learning decimal numbers with textbooks.

• Journal for History of Mathematics
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• v.20 no.2
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• pp.89-108
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• 2007

Finding the lack of meaningful approaches in teaching multiplication of decimal fractions, this paper tries to show from the standpoints of Dewey, Vergnaud and Brousseau that the cognition of ratio and proportion is essential to the understanding of multiplication of decimal fractions. Based upon such posture, this paper compares the characteristics and approaches to multiplication of decimal fractions in Korean and Japanese textbooks. Finally, this paper suggests ways to develop the concept of multiplication of decimal fractions in Korean textbooks.

• Journal of Educational Research in Mathematics
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• v.22 no.2
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• pp.163-178
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• 2012

The efforts to represent the numbers based on the decimal system give us fundamental understanding to construct and teach the concept network on the related knowledge of elementary and secondary school mathematics. In the process to represent natural numbers, integers, rational numbers, real numbers as decimal system, we will classify the extended decimal system. Moreover we will obtain the view to classify real numbers. In this paper, we will study the didactical significance of mathematical knowledge, which arise from process to represent real numbers as decimal system, starting from decimal system representation of natural numbers, and provide the theoretical base about the classification of real numbers. This study help math teachers to understand school mathematics in critical inside-measurement and provide the theore tical background of related knowledge. Furthermore, this study provide a clue to construct coherent curriculum and internal connections of related mathematical knowledge.

• Journal of Elementary Mathematics Education in Korea
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• v.22 no.4
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• pp.475-496
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• 2018

Although the multiplication of decimal fractions is expected to be easy for students to understand because of the similarity to natural numbers multiplication in computing methods, students show many errors in the multiplication of decimal fractions. This is a result of the instruction focused more on skill mastery than conceptual understanding. This study is a basic study for effectively developing a unit of multiplication of decimal fractions. For this purpose, we analyzed the curriculums' performance standards, significance in teaching-learning and evaluation, contents and methods for teaching multiplication of decimal fractions from the 7th curriculum to the revised curriculum of 2015 and the textbooks' activities and lessons. Further, we analyzed preceding studies and introductory books to suggest effective directions for developing teaching unit. As a result of the analysis, three implications were obtained: First, a meaningful instruction for estimation is needed. Second, it is necessary to present a visual model suitable for understanding the meaning of decimal multiplication. Third, the process of formalizing an algorithms for multiplying decimal fractions needs to be diversified.

• Journal of Korean Library and Information Science Society
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• v.37 no.1
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• pp.329-352
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• 2006

This study investigated the background of the first and revised editions of the Han-Un Decimal Classification(HUDC), and analyzed their relationships to and influences on other major related classification systems. HUDC was compiled in 1954 and revised in 1981. HUDC was influenced by NDC in most classes of main classes and mnemonic schedules, and influenced by KDCP in the classes Religion, Language and Literature.

• Proceedings of the IEEK Conference
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• summer
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• pp.225-228
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• 2004

This paper presents a hybrid decimal division algorithm to improve division speed. In a binary number system, non-restoring algorithm has a smaller number of operations than restoring algorithm. In decimal number system, however, the number of operations differs with respect to quotient values. Since one digit ranges 0 to 9 in decimal, the proposed hybrid algorithm employ either non-restoring or restoring algorithm on each digit to reduce iterative operations. The selection of the algorithm is based on the remainder values. The proposed algorithm improves computation speed substantially over conventional algorithms by decreasing the number of operations.

• Education of Primary School Mathematics
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• v.19 no.3
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• pp.193-210
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• 2016

In the $10{\div}2.4$ problem situation, we could find that curious upper and middle level students' solution. They solved $10{\div}2.4$ and wrote the result as quotient 4, remainder 4. In this curious response, we researched how students realize quotient and remainder in division of decimal. As a result, many students make errors in division of decimal especially in remainder. From these response, we constructed fraction based teaching method about division of decimal. This method provides new aspects about quotient and remainder in division of decimal, so we can compare each aspects' strong points and weak points.