Students' understanding of changes in shape and direction in the transformation of plane figures

This study analyzes how the shape and direction of figures are addressed in relation to transformations (translation, reflection, and rotation) in elementary school textbooks from the 7th curriculum to the 2015 revised curriculum, and investigates 5th-grade students' understanding of shape and direction through a test. The results revealed that students interpreted the meaning of shape inconsistently, varying their understanding based on the given context. In tasks requiring students to identify whether the shape or direction of a figure remained unchanged after reflection or rotation, their responses were influenced by the symmetry of each figure. Based on these results, this study discusses the issues inherent in the linguistic expressions and activities related to shape and direction in the textbooks. The conclusion suggests that, for 3rd and 4th graders, the focus should be on observing various combinations of translation, reflection, and rotation, and engaging in art-related activities or interesting problem-solving tasks. Activities that involve identifying whether shapes are the same should be more thoroughly addressed in the 5th and 6th grades, alongside the concept of congruence.