School education should not only provide students with content knowledge but also with effective skills that will be appropriate in their adult lives, such as the competence in solving problems individually or being able to work as a member of a team. Students should be active participants instead of passive listeners in their lessons. There is a wide variety of teaching methods that practicing teachers can choose from to make their lessons varied. The present article explains the outline of an experiment that was based on Spencer Kagan’s cooperative learning focusing on one particular lesson. The mathematics lesson was planned using cooperative teaching techniques and was taught in secondary mathematics education. We analyse how well cooperative learning can be used for improving participation and effective problem-solving in the classroom.

Many research studies have been conducted on students’ or pre-service teachers’ geometric thinking, but there is a lack of studies investigating in-service teachers’ geometric thinking. This paper presents a case study of two high school teachers who attended the dynamic geometry (DG) professional development project for three years. The project focused on the effective use of dynamic geometry software to improve students’ geometry learning. The two teachers were interviewed using a task-based interview protocol about the relationship between two triangles. The interviews, including the teachers' work, were videotaped, transcribed, and analyzed based on the three levels of geometric thinking: recognition, analysis, and deduction. We found that the participating teachers manifested their geometric skills and thinking in constructing, exploring, and conjecturing in the DG environment. The study suggests that the DG environment provides an effective platform for examining teachers' geometric skills, and levels of geometric thinking and encourages inductive explorations and deductive skill development.

This study aims to describe the implication of the Aptitude Treatment Interaction (ATI) model integrated with character values to increase the students’ skill in solving mathematics story problems. This study applied a quasi-experimental research type using a non-equivalent control group design involving two classes with 30 students each. Data was collected using a test instrument for solving mathematics story problem. Data were analyzed using n-gain descriptive statistical analysis to see the increase in students' skill in solving mathematics story world problems. The results showed that the average score of student's aptitude in solving mathematics story problems is 91.26 which is in the category of very high. There is an increase in the students’ ability with score of an n-gain of 0.77 which is in the category of high. In addition, the results of observations related to the implementation of learning model of the ATI with a percentage of 87.5% in the category of very good. Thus, the character-based ATI learning model can be used to increase the students’ skill in solving mathematics story problem. In addition, it accommodates the character of students who are concerned with learning mathematics so that learning goals can be achieved both from cognitive and attitudinal aspects.