Investigating proving skills of 7th grade students in geometry content strandand proof lesson plan implementations

As a natural component of mathematics, proof is an essential tool tounder stand mathematics, to develop higher-order thinking skills and to improve mathematical communication. The importance of proof in mathematics education has been highlighted by research and educational reforms in recent years. This study aims to examine proving abilities of 7th grade students in the field of geometry. It also aims to determine the effects of proof lesson plan implementations on students' proving skills. To do so, the parts that belongs to geometry content strand of a 7th grade text book were examined in terms of proving activities and the lesson plans were prepared based on the proving activities in the text book. Proof Skill Test-1 (PST-1) was administered to investigate students' proving skills. After the implementation of 15-hour lesson plans, the effects of the lessons on the students' proving skills were analyzed by administering Proof Skill Test-2 (PST-2). The participants of this study consisted of 14 students who attend at a public middle school. Semi-structured inter views were conducted with 6 students who were chosen according to the results of the Proof Skill Tests both before and after the lesson plan implementations. The findings of this study show that only %5 of the activities in the 7th grade text book were coded as proving activities. This result is not considered sufficient for students to develop their reasoning and proving skills. According to the PST-1 results of the study; It was determined that 7 of the arguments constructed by the students before the lesson plan implementations were coded as external, 7 of them were coded as empiricale, while only 1 argument was coded analytical argument. According to the PST-2 results after the implementation; 4 arguments were coded as external, 9 as empirical and 19 arguments were coded as analytical arguments. These results show that students improve their proving skills by the lesson plans enriched with proving activities. At the same time, according to the semi-structured inter views conducted with the students, %75 of the students who participated in the lesson plan implementations have a positive attitude towards proof.