Improving the Students’ Critical thinking ability through Problem-Based Learning Model of Scientific Approach on “Linear Equation System of Two Variables” Learning Material

The quality of education today is still a relatively prominent problem in efforts to improve the quality of the national education system. One of the things needs to be improved is the ability to think critically. Critical thinking ability is an important ability to have by students in order to solve the problems faced in changing world. Learning Mathematics by using problem-based learning model of scientific approach is one alternative approach that aims to improve the ability of critical thinking to be trained properly. This study aimed to examine the improvement of students' critical thinking skills, especially on the learning material “Linear Equation System of Two Variables”, both reviewed in whole and in groups of students (upper and lower groups). This research was conducted in junior high school at middle level. The data were collected through tests and questionnaires. The results of the study showed that there was an improvement of critical thinking of 35.29%. The improvement was considered as very low due to the researcher's lack of attention on the level of difficulty among the test items. The level of difficulty was very important to pay attention in order to know how the students' critical thinking skills improvement was. The Student Activities Observation Result showed that the average improvement of the students' active participation every meeting was 83.74% which meant that the students were actively joining every lesson. Furthermore, the data analysis of the students' response questionnaire revealed that students showed a positive attitude toward learning mathematics by using problem-based learning of scientific approach