Construction of Fraction Concept with Interiorization of Two-Level Units Structure Involving Unit Fractions

The purpose of this study is to explore the learning progress of a Stage 1 student who had not yet constructed fractions as measures. To this end, we conducted a teaching experiment with a third-grade student, Taehee over a five-month period (October 2023-February 2024) and established a model for her with describing in detail the changes in her fraction schemes, operations, especially focusing on the characteristic of reversibility. The results indicate that interiorization of the two-level units structure involving units fractions would be a significant milestone of students' fraction concept development, and pedagogical implications and suggestions are discussed accordingly.