• School Mathematics
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• v.9 no.2
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• pp.291-312
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• 2007

As a result of observing the 10-th grade text books on mathematics now in use which show the way of introducing complex numbers for the first time, it is easy to see all the text books on mathematics use a quadratic equation $x^2+1=0$ for a new number i. However, Since using the new number i is artificial, this make students get confused in understanding the way of introducing complex numbers. And students who have problems with the quadratic equation can also have difficulty in understanding complex numbers. On the other hand, by using a coordinate plane with ordered pairs and arrows, students can understand complex numbers better because the number system can be extended systematically through intuitive methods. The problem is that how to bring and use ordered pairs and arrows to introduce complex numbers in highschool mathematics. To solve this problem, in this study, We developed a systematic and visible learning contents which make it possible to study the process of the step-by-step extension of number system that will be applied through elementary and middle school curriculum and all the way up to the introduction of complex numbers. After having applied the developed learning contents to the teaching and learning procedure, we can know that the developed learning contents are more efficient than the contents used in the text books on mathematics now in use.

• Journal of Educational Research in Mathematics
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• v.27 no.4
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• pp.765-789
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• 2017

Arithmetic is the basis of school mathematics and in fact, number and operation in elementary school curriculum is the most basic and essential domain. Even though there has been a consensus that arithmetic should be taught more meaningfully beyond the emphasis of calculation skills and teachers should emphasize the aspect of the arithmetical thinking, it is difficult to find studies which focus on the arithmetical thinking itself. So this research aims to explore the meaning of the arithmetical thinking and extract the arithmetical thinking factors. In order to solve the research problems, we reviewed and analyzed the literatures and then conducted Delphi survey to extract arithmetical thinking factors. From the results of this research, we found the meaning of arithmetical thinking and the arithmetical thinking factors. Especially, the arithmetical thinking consists of 18 factors. It is important to pay attention to students' arithmetical thinking because there are various factors of the arithmetical thinking. It is necessary to identify the aspects of arithmetical thinking reflected in school mathematics based on the meaning of arithmetical thinking and its factors. Based on this, it is possible to find effective teaching and learning methods of arithmetic focusing on the arithmetical thinking.

• Journal of The Korean Association of Information Education
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• v.15 no.3
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• pp.375-385
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• 2011

Computer education is moving its focus from skill oriented education to improving students' creativity and problem solving ability. Thus, the importance of programming education is being strengthened. However, programming education was biased to grammar oriented language that has been limits of students' interest. Robot programming is problem solving itself, and by allowing students to directly see the robot which is the output of programming, can help interest and motivate to the students. In fact, it is still observed that the students are facing difficulties due to various kinds of errors during the programming education. Therefore, this study categorizes and analyzes the errors students are facing during robot programming, and based on that, a support tool to help treat errors developed. The developed supporting system for error solving reduces the frequency of errors and provides the set of coding instruction, NXC language and error message in Korean, examples and detailed information for each stage of education, function removing major coding errors, and code sorting and indication of row number. This study also confirmed that the supporting tool is helpful in reducing and solving errors after input.

• Journal of the Korean Dietetic Association
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• v.12 no.1
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• pp.55-67
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• 2006

The purpose of this study was to compare the food behavior and nutrient intakes, and the analysis of constituent parts of blood related to iron nutrition conditions and to investigate the correlation between iron nutrition conditions and obesity. Each subject was assigned to one of such as normal(n=55) and obese groups(n=60) according to their obesity index. Their nutritional status, serum iron status were evaluated based in 24-hr dietary recalls, questionnaire and blood analysis. The mean age of the normal group(10.76 years) and that of the obese group(10.95 years) made little difference. The height(p<0.05), weight(p<0.001), and obesity index(p<0.001) in the obese group were higher than those of the normal group in every respect. The 63.55% of the subject of this study gave an answer 'They eat breakfast daily', and the frequency of eating breakfast made little difference. The average intakes of energy were 1669.44 kcal(84.19% of EER) in the obese group and 1673.59 kcal(86.72% of EER) in the normal group respectively, which made little difference between two groups. The intake of nutrients such as calcium and folate was as insufficient as below 75% of RI. The heme iron intake of the obese group was low that of the normal group(p<0.05). Among the major 20 iron resources the iron intake through animal food intake were 1.43 mg(12.00%) in the obese group and 1.93 mg(17.72%) in the normal group respectively. The rating of iron condition in the blood showed that the number of red blood cell(p<0.01), the hemoglobin(p<0.001), and hematocrit(p<0.01) of the obese group were lower than those of the normal group. These results suggest that there should be the right choice of food according to its bioavailability and nutritive guidance to appropriate food behavior, in addition to increasing iron intake to improve iron nutrition conditions of obese male elementary school students.

• Education of Primary School Mathematics
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• v.13 no.2
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• pp.55-66
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• 2010

The basic direction of mathematical education for the 21st century is focused on helping student to understand mathematics and developing their problem solving abilities, mathematical disposition and mathematical thinking. Elementary mathematics teachers should help students make sense of mathematics, confident of their ability, and make learning environment comfortable for students to participate in. Through making activities 1 to 100 with digits 1,9,9,6, students improved the interest and preference of students about mathematics. This game is useful to foster students' mathematical thinking(concepts of exponential number expression, roots concept(${\sqrt}$), gauss function([])) and mathematical disposition. If students are helped to be interested in mathematics through mathematical games, they regard mathematics as interesting and challengeable subject to let themselves think many ways.

• Journal of The Korean Association of Information Education
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• v.24 no.5
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• pp.483-494
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• 2020

With the advent of the 4th Industrial Revolution, interest in AI education is increasing. In order to cultivate talented people with AI competencies who will lead the future, AI education must be conducted in a sound manner at the school site. Although AI education is being conducted at home and abroad, it was determined that the role of the AI education platform is important to implement better AI education, so this study investigated the perception of experts on the AI education platform. A perception survey was conducted based on five criteria: teaching and learning management, educational contents, accessibility, performance of AI education platform, and level suitability of elementary school students. As a results, the number of 103 educational experts selected 'Entry' as the most proper platform among the eight platforms - 'Machine learning for Kids', 'Teachable Machine', 'AI Oceans(code.org)', 'Entry', 'Genie Block', 'Elice', 'mBlock' and etc. Analysis shows that this is because 'Entry' provides quality educational content, has convenient accessibility, is easy to manage teaching and learning, as well as an AI education platform suitable for the level of elementary school. In order to apply various AI education platforms to the school field, it is necessary to train teachers in AI-related training to train them as AI education experts, and to continuously provide opportunities to experience AI education platforms. In this study, there are limitations to what is called 'a population perception survey'. because only 103 people were surveyed, and most of the experts are working in a specific area(Gyeonggi-do). In the future, it is judged that research targeting experts at the national level should be conducted to supplement these limitations.

• Journal of The Korean Association For Science Education
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• v.28 no.5
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• pp.495-505
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• 2008

The purpose of this study was to analyze the level of evidence used in gifted elementary students' argumentation. The subjects were 15, 5th and 6th grade students selected in the Science Education Institute for Gifted Youth in K University. After the argumentation task was given to students 2 weeks ago, the students grouped themselves in the affirmative and negative and took part in a debate for 2 hours. Their argumentation process was observed, recorded and transcribed for analysis. Transcribed data was given a Protocol Number according to priority and was examined to find out what were the characteristics when students participated in the task. The evidence used in argumentation was graded from level 1 to level 6 according to Perella's Hierarchy of Evidence and the rate of frequency classified by the level was expressed in graph. Students used Level 1- Level 2 evidence above 50% without for or against task. They had weak argumentation making use of low-level evidence such as individual experience, opinion and another person's experience rather than objective evidences. On the other hand, students commented on the lack of opponent's evidence when they could not trust an opponent's evidence. If one team asked the other to present more evidence but could not, they disregarded the question and turned to another topic. And in cases where the opponent team refuted with evidences of high level, the other team just repeated their claim or evaded the rebuttal. The students tended to complete the argument without the same conclusions with some interruptions. The results show that we need an educational programs including scientific argumentation for science-gifted elementary school students.

• East Asian mathematical journal
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• v.27 no.2
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• pp.163-180
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• 2011

The purpose of this study is to look for the plan of reconstructing a textbook through error analysis and the process of its correction in numbers and operations of the first grade. The Research materials are collected and analyzed through the journal about every lessons, the recording sheets of students' activity, the recording videotapes during lessons, the individual interview and observation. This study investigated 4 errors which are useful for reconstructing textbook, the errors of understanding relation between numerical expression and number line, the errors of drawing-strategy, the errors of understanding relation between additive expression and subtractive expression, the errors of subtraction has to be regrouped. The errors are classified into some types and analyzed focusing on content of each error. Reinstructing are carried out based on material analyzed for correcting errors.

• Journal of Nutrition and Health
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• v.23 no.5
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• pp.317-328
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• 1990

This reseach was undertaken to investigate the nutritional contents of lunchboxes of 5th grade students in the elementary school living in Jinju city. The survey was conducted from July 4 to July 7, 1988. Cereals and side dishes in the lunch box were weighed and nutrients were analyzed from the food composition table. Questionaires were used to determine family background and the food preference. The results were summarized as follows : 1) The average education of mother was 10 years and the average number of children in the family was 2.8. 2) The average food weight of 151 boys was 289g and that of 164 girls was 253g. The average number of side dishes was 1.7. 3) The average nutritional value and the percentage of Recommended Dietary Allowances of boys were calorie 578 Cal, 75%, protein 24.6g, 113%, calcium 128mg, 55%, iron 3.89mg, 78.0 %, vitamin A 807IU, 122 %, thiamin 0.32mg, 81 %, riboflavin 0.26mg, 56 %, niacin 4.07mg, 81 %, ascorbic acid 6.33mg, 38%. 4) The average nutritional value and the percentage of Recommended Diatary Allowances of girls were calorie 547 Cal, 82 %, protein 23.0g, 113 %, calcium 135mg, 58 %, iron 3.37mg, 56 % ,vitamin A 911IU, 137 % , thiamin 0.27m9, 732 % , riboflavin 0.26mg, 64 % , niacin 4.03mg, 93 % , ascorbic acid 7.40mg, 44 % . 5) The calorie ratios of carbohydrate, protein and fat from boys and girls were 75 : 18 : 7 and 76 : 17 : 7, respectively. 6) The favorite food for cereals were plain rice, breads, noodles, rice with beans and the favorite food for side dishes were ham, sausage, beef and chicken.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.4
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• pp.583-599
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• 2016

In this paper, aspects of equalities with monomial left-hand side presented in Korean elementary school mathematics textbooks are analyzed focusing on the component of expressions. According to this analysis, the textbooks deal with equalities with monomial left-hand side as though the students already know them, rather than to introduce and deal with them systematically. In this paper, the following four suggestions based on this analysis are proposed as conclusions. First, A-type equalities (with one kinds of calculation symbols and two or more numbers, variables, denominative numbers in the right-hans side) and B-type equalities (with two or more kinds of calculation symbols and two or more numbers, variables, denominative numbers in the right-hans side) may need to be introduced by the explicit description. Second, it is necessary to establish clearly the order of dealing with numeric expressions, expressions with ${\Box}$(blank) expression, expressions with words, expressions with ${\Box}$(variable), expressions with variables. Third, it needs to be noted that equalities with monomial left-hand side cab be used with a variety of meanings. Fourth, it is necessary to widen the range of the number constituting equalities with monomial left-hand side to the natural number 0 and as well as fractions, decimals.