• School Mathematics
• /
• v.9 no.1
• /
• pp.99-117
• /
• 2007

In this paper it is discussed how children develop their logical reasoning beyond difficulties in the process of making sense of division with decimals in the classroom setting. When we consider the gap between mathematics at elementary and secondary levels, and given the logical nature of mathematics at the latter levels, it can be seen as important that the aspects of children's logical development in the upper grades in elementary school should be clarified. This study focuses on the teaching and learning of division with decimals in a 5th grade classroom, because it is well known to be difficult for children to understand the meaning of division with decimals. It is suggested that children begin to conceive division as the relationship between the equivalent expressions at the hypothetical-deductive level detached from the concrete one, and that children's explanation based on a reversibility of reciprocity are effective in overcoming the difficulties related to division with decimals. It enables children to conceive multiplication and division as a system of operations.

• Journal of the Korean School Mathematics Society
• /
• v.11 no.2
• /
• pp.285-298
• /
• 2008

According to the 7th curriculum, irrational numbers should be introduced using infinite decimals in 9th grade. To do so, the relation between rational numbers and decimals should be explained in 8th grade. Preceding studies remarked that middle school students could understand the relation between rational numbers and decimals through the division appropriately. From the point of view with the arithmetic handling activity, I analyzed that the integers and terminating decimals was explained as decimals with repeating 0s or 9s. And, I reviewed the equivalent relations between irrational numbers and non-repeating decimals, rational numbers and repeating decimals. Furthermore, I suggested an alternative method of introducing irrational numbers.

• Journal of Elementary Mathematics Education in Korea
• /
• v.15 no.3
• /
• pp.533-557
• /
• 2011

The purpose of this study was to understand PCK to improve professionalism of teachers and derive implications about proper teachings methods. For achieving these research purposes, different PCK and teaching methods in class of three teachers(A, B, C) were compared and analyzed targeting division of decimals for 6th grade. For this study, criteria of PCK analysis of teachers was set, PCK questionnaires were produced and distributed, teachers had interviews, PCK of teachers were analyzed, division of decimals class for 6th grade was observed and analyzed, and PCK of teachers and their classes were compared. The implications deriving from comparative analyzing PCK and classes are as follows. First of all, there was a close relation between PCK and classes, leading to a need for efforts of increasing PCK of teachers in every field in order to realize effective classes. Secondly, self study and in-service training are needed to enhance PCK of teachers. Thirdly, more of expertises and materials have to be provided on the instruction manual for teachers.

• The Mathematical Education
• /
• v.50 no.3
• /
• pp.309-327
• /
• 2011

In this paper, we extended the division algorithm for the integers to the finite decimals. Though the remainder for the finite decimals is able to be defined as various ways, the remainder could be defined as 'the remained amount' which is the result of the division and as "the remainder" only if 'the remained amount' is decided uniquely by certain conditions. From the definition of "the remainder" for the finite decimal, it could be inferred that 'the division by equal part' and 'the division into equal parts' are proper for the division of the finite decimal concerned with the definition of "the remainder". The finite decimal, based on the unit of measure, seemed to make it possible for us to think "the remainder" both ways: 1" in the division by equal part when the quotient is the discrete amount, and 2" in the division into equal parts when the quotient is not only the discrete amount but also the continuous amount. In this division context, it could be said that the remainder for finite decimal must have the meaning of the justice and the completeness as well. The theorem of the division algorithm for the finite decimal could be accomplished, based on both the unit of measure of "the remainder", and those of the divisor and the dividend. In this paper, the meaning of the division algorithm for the finite decimal was investigated, it is concluded that this theory make it easy to find the remainder in the usual unit as well as in the unusual unit of measure.

• Education of Primary School Mathematics
• /
• v.21 no.3
• /
• pp.309-327
• /
• 2018

This study is a case study of an elementary school teacher's reflection and practice in the process of planning, executing and criticizing his lesson on division with decimals. The purpose of this study was to clarify what kinds of problems an elementary school teacher was thinking about and how his focus was changing in the process of planning and executing a lesson and criticizing his lesson with his peers. The teacher was set in three periods: a teacher planning a lesson, a teacher executing a lesson, and a teacher criticizing his or her own lesson. Each period was analyzed in eight aspects: Establishing the goals for mathematics, implementing tasks, connecting mathematical representations, facilitating mathematical discourse, posing questions, building procedural fluency from conceptual understanding, supporting productive struggles, and using evidences of students' thinking.

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

• The Journal of the Korea Contents Association
• /
• v.17 no.9
• /
• pp.437-448
• /
• 2017

This study was conducted as a qualitative case study for examining what transformed primary concepts and transformed schemas were formed for the addition of decimals and how they were formed, and how the relational understanding of the addition of decimals was in three 3rd grade elementary school children who had studied the primary concepts of division, fraction and decimal. That is, this study investigated how the subjects approached problems of decimal addition using transformed primary concepts and transformed schemas formed by themselves, and how the subjects formed concepts and transformed schemas in problem solving. According to the results of this study, transformed primary concepts and transformed schemas formed through the learning of the primary concepts of division, fraction, and decimal functioned as important factors for the relational understanding of decimal addition.

• Research in Mathematical Education
• /
• v.19 no.2
• /
• pp.89-100
• /
• 2015

The study investigated pre-service teachers' knowledge and computational skills by using Triangular Arithmagon. Participants included 90 pre-service teachers from two schools in the United States and Taiwan. The Triangular Arithmagons Test (TAT) was used to measure pre-service teachers' performance in whole number, fractions, and decimals operations (i.e., addition, subtraction, multiplication, and division), each of which included level-1 (basic) and level-2 (advanced) tests. MANOVA analysis was performed to compare the performance between teachers from the United States and Taiwan. Results indicated that overall, pre-service teachers in Taiwan outperformed those in the United States, especially on the advanced-level tests. Pre-service teachers in the United States were found to have poor ability of solving complex operation problems. Different curriculum plans and teaching methods may lead to the performance gap between the two countries.

• Education of Primary School Mathematics
• /
• v.24 no.2
• /
• pp.103-114
• /
• 2021

In this study I recognized the problems with the use of the terms 'quotient' and 'reminder' in the division of decimal and explored ways to improve them. The prior studies and current textbooks critically analyzed because each researcher has different views on the use of the terms 'quotient' and 'reminder' because of the same view of the values in the division calculation. As a result of this study, I proposed to view the result 'q' and 'r' of division of decimals by division algorithms b=a×q+r as 'quotient' and 'reminder', and the amount equal to or smaller to q the problem context as a final 'result value' and the residual value as 'remained value'. It was also proposed that the approximate value represented by rounding the quotient should not be referred to as 'quotient'.

• School Mathematics
• /
• v.14 no.1
• /
• pp.45-64
• /
• 2012

The purpose of the present study was to investigate middle grades (Grade 5-7) mathematics teachers' knowledge of partitive fraction division. The data were derived from a part of 40-hour professional development course on fractions, decimals, and proportions with 13 in-service teachers. In this study, I attempted to develop a model of teachers' way of knowing partitive fraction division in terms of two knowledge components: knowledge of units and partitioning operations. As a result, teachers' capacities to deal with a sharing division problem situation where the dividend and the divisor were relatively prime differed with regard to the two components. Teachers who reasoned with only two levels of units were limited in that the two-level structure they used did not show how much of one unit one person would get whereas teachers with three levels of units indicated more flexibilities in solving processes.