• Communications of Mathematical Education
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• v.18 no.1 s.18
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• pp.73-87
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• 2004

현장에서 수업을 하다 보면 의외로 학생들이 곱셈구구는 잘 외우고 있지만 곱셈의 개념에 대해서는 잘 모르고 있다는 것을 많이 발견할 수 있다. 이것은 곱셈에 대한 개념을 도입할 때 학생들이 왜 곱셈을 배우는가에 대해서 스스로 절실하게 생각해 보고 발견해 보는 경험이 부족했기 때문이라고 생각한다. 곱셈이 왜 필요하고 곱셈식으로 나타내는 것이 얼마나 좋은 방법인지 학생들이 깨달아 덧셈구조에서 곱셈구조로의 개념의 변화가 일어날 수 있도록 지도한다면 이러한 문제점을 어느 정도 해결할 수 있지 않을까 생각해본다. 따라서, 본 연구에서는 자연수의 곱셈에 대한 이론적 배경과 교육과정을 알고 이를 바탕으로 수학교육 이론에 근거한 자연수의 곱셈의 교수-학습 지도 방안에 대하여 거시적 입장에서 고찰해 보고자 한다.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.1
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• pp.195-214
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• 2017

The standardized algorithm of natural number multiplication simplify the procedure of arithmetic. In the case of multiplication algorithm with regrouping, we write small the carrying number on the multiplicand. But, teachers and students have to make their own way about the case of two digits multipliers, because Korean elementary mathematics textbooks just deal with the case of the one digit multipliers. In this study, we investigated Korean current elementary mathematics textbooks related to multiplication algorithm with regrouping, and analyzed the result of research on the real condition about marking the carrying number. Besides, we reviewed the guidance contents of algorithm of natural number multiplication in Finland's math textbook and literature. By conclusions, we suggest several implications as followed; First, we need some examples of the way to mark the carrying number in teacher's guidance books and textbooks. Second, teachers try for students to feel the good points of the systematic ways to mark the carrying number. Third, teachers understand algorithm of natural number multiplication and the alternative ways about marking the carrying number.

• School Mathematics
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• v.13 no.2
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• pp.267-286
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• 2011

In this paper I investigated the historical developments of the algorithms for multiplication of natural numbers. Through this analysis I tried to describe more concretely what is to understand the common algorithm for multiplication of natural numbers. I found that decomposing dividends and divisors into small numbers and multiplying these numbers is the main strategy for carrying out multiplication of large numbers, and two decomposing and multiplying processes are very important in the algorithms for multiplication. Finally I proposed some implications based on these analysis.

• Journal of Educational Research in Mathematics
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• v.22 no.2
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• pp.293-309
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• 2012

The algorithm of natural number multiplication is one of the basic topics of elementary school mathematics. Mastery of algorithm and understanding of the principles are important educational aims. In this paper we analyzed elementary school mathematics textbooks of South Korea, the United States, Singapore, Japan. As a result of analysis, we found out that there are much differences in the teaching of multiplication with three numbers, '${\times}10$', and '${\times}tens$'. We suggested some implication for the teaching of algorithm of natural number multiplication.

• School Mathematics
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• v.11 no.4
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• pp.685-706
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• 2009

This dissertation is aimed to investigate the reason why a contextualization is needed to help the meaningful teaching-learning concerning multiplications and divisions of fractions, the way to make the contextualization possible, and the methods which enable us to use it effectively. For this reason, this study intends to examine the differences of situations multiplying or dividing of fractions comparing to that of natural numbers, to recognize the changes in units by contextualization of multiplication of fractions, the context is set which helps to understand the role of operator that is a multiplier. As for the contextualization of division of fractions, the measurement division would have the left quantity if the quotient is discrete quantity, while the quotient of the measurement division should be presented as fractions if it is continuous quantity. The context of partitive division is connected with partitive division of natural number and 3 effective learning steps of formalization from division of natural number to division of fraction are presented. This research is expected to help teachers and students to acquire meaningful algorithm in the process of teaching and learning.

• 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.

• Communications of Mathematical Education
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• v.35 no.4
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• pp.505-525
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• 2021

In this study, we investigated how multiplication by 2-digit numbers had been taught in elementary mathematics textbooks of Korea, Japan, Singapore, and USA. As a result of analysis, we found as follows. Korean textbooks do not teach the multiplication by 10 and the multiplication by power of 10, but Japanese, Singapore, and US textbooks explicitly teach related content. In the '×tens' teaching, Japanese and American textbooks teach formally the law of association of multiplication applied in the process of calculating the partial product of multiplication. The standard multiplication algorithm generally followed a standard method of recording partial product result according to the law of distribution, but the differences were confirmed in the multiplication model, the teaching method of the law of distribution, and the notation of the last digit '0'. Based upon these results, we suggested some proposals for improving the multiplication teaching.

• School Mathematics
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• v.11 no.1
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• pp.17-37
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• 2009

Concept and model of multiplication is not single. Concepts of multiplication can be classified into three cases: repeated addition, times idea, pairs set. Models of multiplication can be classified into four cases: measurement, rectangular pattern, combinatorial problem, number line. Among diverse cases of multiplication's concept and model, which case does elementary mathematics education lay stress on? This question is a controvertible didactical point. In this thesis, (1) mathematical and didactical analysis of multiplication's concept and model is performed, (2) a concrete program of teaching multiplication which is based on times idea is contrived, (3) With this new program, the teaching experiment is performed and its result is analyzed. Through this study, I obtained the following results and suggestions. First, the degree of testee's understanding of times idea is not high. Secondly, a sort of test problem which asks the testee to find times value is more easy than the one to find multiplicative resulting value. Thirdly, combinatorial problem can be handled as an application of multiplication. Fourthly, the degree of testee's understanding of repeated addition is high. In conclusion, I observe the fact that this new program which is based on times idea could be a alternative program of teaching multiplication which could complement the traditional method.

• School Mathematics
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• v.15 no.4
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• pp.889-920
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• 2013

The aim of this study is to look into the didactical background for introducing the concept of multiplication and teaching multiplication facts in elementary school mathematics and offer suggestions to improve teaching multiplication in the future. In order to attain these purposes, this study deduced and examined concepts of multiplication, situations involving multiplication, didactical models for multiplication and multiplication strategies based on key ideas with respect to the didactical background on teaching multiplication through a theoretical consideration regarding various studies on multiplication. Based on such examination, this study compared and analyzed textbooks used in the United States, Finland, the Netherlands, Germany and South Korea. In the light of such theoretical consideration and analytical results, this study provided implication for improving teaching multiplication in elementary schools in Korea as follows: diversifying equal groups situations, emphasizing multiplicative comparison situations, reconsidering Cartesian product situations for providing situations involving multiplication, balancing among the group model, array model and line model and transposing from material models to structured and formal ones in using didactical models for multiplication, emphasizing multiplication strategies and properties of multiplication and connecting learned facts and new facts with one another for teaching multiplication facts.

• 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.