Mathematical critical thinking ability of students at vocational highschool (adolescence)

Mathematical critical thinking ability is very important for vocational students and at that level critical thinking ability is currently developing. The research has a purpose to describe mathematical critical thinking ability based on the age range of vocational high school students. With purposive sampling, six students from the Vocational High School (SMKN 4 Bandung) were chosen as research subjects. This qualitative-descriptive research uses test instruments and interview guidelines. The data interpretation of this research is produced based on these indicators: 1) Giving an answer with relevant reasons. 2) Giving a solution with explanation to check a correct result. 3) Analyzing and clarifying questions, answers, and arguments. 4) Evaluating and considering source of truth. The result of this research is the students with 15 years and 16 years old were able to complete the first, second and fourth indicators, otherwise 17 years old could complete all indicators.The conclusion of the research is math critical thinking ability between 15, 16, 17 years old are relative same.