길예빈 Kil Yeabin , 장혜원 Chang Hyewon

DOI:10.7468/jksmec.2025.28.3.95 JANT Vol.28(No.3) 95-110, 2025

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This study investigates the informal strategies employed by fifth-grade elementary school students when multiplying decimals before learning decimal multiplication. A qualitative case analysis was conducted on the solutions of 26 students who had not learned decimal multiplication, focusing on how and what informal knowledge they used. The results indicate that converting decimals into fractions was the most frequently used approach, followed by strategies based on natural number calculation, repeated addition, and visual representations. There were also differences in the types of informal knowledge utilized and the correct answer rates by type of number. While students demonstrated meaningful mathematical reasoning based on informal knowledge, several errors―such as error in decimal point placement―were also observed. The findings reveal that informal knowledge serves as a critical foundation for forming new mathematical concept and principles and emphasize the importance of instructional approaches that recognize and build upon such knowledge to address misconceptions and connect informal knowledge and formal knowledge.

박예진 Park Yejin , 방정숙 Pang Jeongsuk

DOI:10.7468/jksmec.2025.28.3.111 JANT Vol.28(No.3) 111-128, 2025

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Curriculum resources, such as teacher guides, are important because they contain educative features that support effective learning for teachers. However, few studies have examined how these features affect teachers' learning and lesson planning. In this study, we analyzed the educative features of ten guidebooks, using the third-grade pictograph unit as an example. We then provided a teacher with abundant curriculum resources in educative features according to the developmental flow of each lesson, and analyzed the changes in his lesson plans. We found that, compared to his initial lesson plans, the teacher consistently utilized a variety of educative features in the revised lesson plans. In particular, the revised plans reflected the classroom context and teacher intentions and included directives that facilitated student discussion. In contrast, using personalized instruction remained passive perceptions, leading little incorporation into lesson plans. The teacher attempted to use manipulative materials and technology but had many limitations. Based on these findings, this study provides implications for teacher learning and the utilization of curriculum resources abundant in educative features.

이상희 Lee Sang Hee , 박만구 Park Mangoo

DOI:10.7468/jksmec.2025.28.3.129 JANT Vol.28(No.3) 129-147, 2025

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This study aimed to explore the developmental changes in finger gestures and their cognitive functions during counting and arithmetic tasks in a 4-year-old child. Vygotsky’s sociocultural approach and Radford’s semiotic-cultural approach were employed as theoretical frameworks to analyze the cognitive roles of gestures. A qualitative case study method was used to closely observe and analyze episodes from the child’s counting and arithmetic activities. The findings revealed that finger gestures functioned as tools for arranging and manipulating quantities and for structuring number concepts. In particular, gestures supported the internalization of structures such as “10 plus something” and the reorganization of quantities through visual-spatial arrangements. However, in asymmetrical arrangements or comparative subtraction situations, inconsistencies in gesture use emerged, occasionally leading to cognitive conflict but also providing opportunities for cognitive shifts and strategic readjustment. These results suggest that gestures serve not merely as expressive tools but as cognitive resources mediating conceptual development, highlighting the educational potential of nonverbal representations in mathematics learning.