This research aimed to describe the mathematical reasoning ability of
eight grade students in SMP Negeri 2 Karanglewas viewed from the gender
difference. The method used was descriptive qualitative research with Miles and
Huberman model including data reduction, data display and conclusion. The
samples were taken through purposive sampling technique. The students were
classified into male and female category. 4 students were chosen from each
category as interviewee. The data were collected through test, interview, and
documentation. The findings of the research show that the mathematical
reasoning ability of male group involves the ability to propose hypothesis, to do
manipulation of mathematics, to draw a conclusion from given statement, and to
examine the validity of an argument. Moreover, the mathematical reasoning
ability of female group involves the ability to propose hypothesis, to do
manipulation of mathematics, to draw a conclusion from given statement, but
incapably to examine the validity of an argument.