Primary mathematics teacher candidates' geometric level of thinking and learning deficiencies in geometry

The aim of this study is to reveal the geometric thinking levels of primary school mathematics teacher candidates and their learning deficiencies towards geometry. This research is a mixed method research. The nested (embedded) design, which is one of the mixed method designs, was used in the study. The study group of this research consists of a total of 84 teacher candidates studying in the 1st year of the Department of Primary Education Mathematics Teaching in the Faculty of Education of a medium-sized state university in the Black Sea Region in the 2020-2021 academic year. In this study, "Van Hiele Geometry Test" was used as a quantitative data collection tool in order to determine the geometric thinking levels of primary school mathematics teacher candidates. In the qualitative data collection part of the study, which was embedded in the quantitative data, a section was added in the form of "justification" for each item in the Van Hiele geometric thinking test, in which the teacher candidates were asked to explain the multiple-choice questions. It is aimed to collect more in-depth data by presenting the "justification" directive in the detection of learning deficiencies. In this study, while quantitative data were predominantly used, qualitative data were used for supporting and explanatory purposes. Quantitative data were analyzed using the SPSS 23.0 package program, and frequency (f) and percent (%) values were calculated using descriptive statistical methods. In the analysis of qualitative data, content analysis method, which is one of the qualitative analysis data methods, was used. As a result of the analysis of the data obtained, it has been detected that nearly half (41.6%) of the primary school mathematics teacher candidates were at the Level 3 Experience Based Inference Level, 29.7% at the Level 4 Formal Deduction / Inference level, and 7.1% at the Level 5 Highest Level / Ability to See Relationships. The learning deficiencies of teacher candidates have been observed as inability to express inclusive relationships between quadrilateral classes, incomplete knowledge of the critical properties of polygons, inability to order simple propositions, inability to draw conclusions based on logic, and limited understanding.