• 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 Elementary Mathematics Education in Korea
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• v.11 no.1
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• pp.1-21
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• 2007

The purpose of this study was to propose instructional methods using base-ten blocks in teaching the multiplication of decimal for 5th grade students by analyzing the process of their conceptual comprehension of multiplication of decimal. The students in this study were found to understand various meanings of operations (e.g., repeated addition, bundling, and area) by modeling them with base-ten blocks. They were able to identify the algorithm through the use of base-ten blocks and to understand the principle of calculations by connecting the manipulative activities to each stage of algorithm. The students were also able to determine whether the results of multiplication of decimal might be reasonable using base-ten blocks. This study suggests that appropriate use of base-ten blocks promotes the conceptual understanding of the multiplication of decimal.

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.2
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• pp.409-416
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• 2024

With the expansion of floating-point operation requirements for fast high-speed data signal processing and logic operations, the speed of the floating-point operation unit is the key to affect system operation. This paper studies the performance characteristics of different floating-point multiplier schemes, completes partial product compression in the form of carry and sum, and then uses a carry look-ahead adder to obtain the result. Intel Quartus II CAD tool is used for describing Verilog HDL and evaluating performance results of the floating point multipliers. Floating point multipliers are analyzed and compared based on area, speed, and power consumption. The FMAX of modified Booth encoding with Wallace tree is 33.96 Mhz, which is 2.04 times faster than the booth encoding, 1.62 times faster than the modified booth encoding, 1.04 times faster than the booth encoding with wallace tree. Furthermore, compared to modified booth encoding, the area of modified booth encoding with wallace tree is reduced by 24.88%, and power consumption of that is reduced by 2.5%.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.1
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• pp.1-18
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• 2011

The purpose of this study was to investigate the effects of estimation strategy on placing decimal point in multiplication and division of decimals. To examine the effects of improving calculation ability and reducing decimal point errors with this estimation strategy, the experimental research on operation with decimal was conducted. The operation group conducted the decimal point estimation strategy for operating decimal fractions, whereas the control group used the traditional method with the same test paper. The results obtained in this research are as follows; First, the estimation strategy with understanding a basic meaning of decimals was much more effective in calculation improvement than the algorithm study with repeated calculations. Second, the mathematical problem solving ability - including the whole procedure for solving the mathematical question - had no effects since the decimal point estimation strategy is normally performed after finishing problem solving strategy. Third, the estimation strategy showed positive effects on the calculation ability. Th Memorizing algorithm doesn't last long to the students, but the estimation strategy based on the concept and the position of decimal fraction affects continually to the students. Finally, the estimation strategy assisted the students in understanding the connection of the position of decimal points in the product with that in the multiplicand or the multiplier. Moreover, this strategy suggested to the students that there was relation between the placing decimal point of the quotient and that of the dividend.

• School Mathematics
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• v.12 no.3
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• pp.371-388
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• 2010

The goals of this study are to inquire middle school students' understanding about prime number and to propose pedagogical implications for school mathematics. Written questionnaire were given to 198 Korean seventh graders who had just finished learning about prime number and prime factorization and then 20 students participated in individual interviews for member checks. In defining prime and composite numbers, the students focused on distinguishing one from another by numbering of factors of agiven natural number. However, they hardly recognize the mathematical connection between prime and composite numbers related on the multiplicative structure of natural number. This study suggests that it is needed to emphasize the conceptual relationship between divisibility and prime decomposition and the prime numbers as the multiplicative building blocks of natural numbers based on the Fundamental Theorem of Arithmetic.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.839-842
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• 2006

대부분의 불리언 행렬에 대한 연구는 두 불리언 행렬의 곱셈에 초점을 두고 있으며 모든 불리언 행렬을 대상으로 한 곱셈에 대한 연구는 최근에야 극히 소수의 연구결과가 보이고 있다. 이 연구들은 모든 불리언 행렬 사이의 곱셈 실행시간을 개선시켰으나 연속된 세 개의 모든 lxn, nxm, mxk 불리언 행렬에 대한 곱셈은 아직 많은 개선이 필요하다. 본 논문은 모든 $l{\times}n,\;n{\times}m,\;m{\times}k$ 불리언 행렬의 곱셈 실행시간을 보다 개선할 수 있는 이론을 제시하고 이를 적용한 불리언 행렬 연속곱셈의 실행결과에 대하여 논한다.

• Journal of Elementary Mathematics Education in Korea
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• v.23 no.1
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• pp.1-17
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• 2019

In this study, prospective teachers were involved in arranging the teaching sequence of multiplication and division of fractions and decimal numbers based on their experience and knowledge of school mathematics. As a result, these activities provided an opportunity to demonstrate the prospective teachers' perception. Prospective teachers were able to learn the knowledge they needed by identifying the differences between their perceptions and curriculum. In other words, prospective teachers were able to understand the mathematical relationships inherent in the teaching sequence of multiplication and division of fractions and decimal numbers and the importance and difficulty of identifying students' prior knowledge and the effects of productive failures as teaching methods.

• Education of Primary School Mathematics
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• v.25 no.3
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• pp.251-278
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• 2022

The purpose of this study is to obtain implications for mathematical education by analyzing how the multiplication and division of decimal numbers are presented in the elementary mathematics textbooks in Korea, Japan, Singapore, and Finland. Compared to the fact that students often have misconceptions about multiplication and division of decimal numbers, there have been not many comparative studies in recent elementary mathematics textbooks. For this study, we selected elementary mathematics textbooks those are widely used in Japan, Singapore, and Finland along with Korean elementary mathematics textbooks. We chose the textbooks because the students in the selected countries have scored high in international achievement studies such as TIMSS and PISA. The analysis was examined in terms of elementary mathematics curriculum related to multiplication and division of decimal numbers, introduction and content, real-life situations, use of visual models, and formalization methods of algorithms. As a result of the study, the mathematics curricula related to multiplication and division of decimal numbers includes estimation in Korea and Finland, while Japan and Singapore emphasize real-life connections more, and Finland completes the operations in secondary schools. The introduction and content are intensively provided in a short period of time or distributed in various grades and semesters. The real-life situations are presented in a simple sentence format in all countries, and the use of visual models or formalization of algorithms is linked to the operations of natural numbers in unit conversions. Suggestions were made for textbook development and teacher training programs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2341-2349
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• 2015

The commonly used Goldschmidt's floating-point divider algorithm performs two multiplications in one iteration. In this paper, a tentative error corrected K'th Goldschmidt's floating-point number divider algorithm which performs K times multiplications in one iteration is proposed. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications per an operation in single precision and double precision divider is derived from many reciprocal tables with varying sizes. In addition, an error correction algorithm, which consists of one multiplication and a decision, to get exact result in divider is proposed. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a divider unit. Also, it can be used to construct optimized approximate reciprocal tables.