Critical Thinking of Pre-service Teachers in Generalizing Mathematical Idea on the Topic of Set

It is undeniable that the ability of critical thinking is important as mentioned in 21st century skills. Teachers, as the main educator at school, are required to think critically in every decision while they are teaching a mathematical topic. However, a number of empirical field observation have pointed out that most of the teacher unable to response to the students’ difficulty due to inability to analyze the situation and think critically. This study aims to find out the critical thinking of pre-service teacher and to what extend they are able to present their idea, especially on the topic of set, in the class. 32 pre-service teachers were given the set of generalizability problems and situational problems from which the pre-service teachers’ critical thinking were elicited. The findings suggest that a number of pre-service teachers are able to generalize the mathematical idea, especially by using factual generalization. This suggest that generalizing the set concept deductively using symbol only become difficulty for the pre-service teachers. In addition, however, regardless the generalization, some of them were having difficulties in presenting an understandable content. Keywords— critical thinking, generalize mathematical idea, set, pre-service teacher