Knowing the mathematization process was important for teacher to choose the best model learning. In solving problem, the junior high school students were using their own mathematization process. This research aimed to describe the horizontal and vertical mathematization process of junior high school students with high mathematical ability in solving contextual problem of fraction. For this purpose, the researcher selected one student as the research subjects representing high mathematical ability. The type of research was descriptive qualitative research and used one contextual problem that was related of fraction.

 

The research subjects was determined by mathematical ability test (TKM). There were seven classes of 7^th grade of SMPN 1 Tambakboyo, 7^th G class was chosen purposively. Thirty four students of chosen class were given mathematical ability test (TKM). Then, they were divided into three groups based on the ability which were high ability group, medium ability group, and low ability group. Researcher took one subject from high ability group to be research subject. Then, researcher gave the profile mathematization process test (TPPM) to know the horizontal and vertical mathematization process. The semi-structured interview was utilized to invstigate the answered of TPPM.

 

The result of this research were: the high mathematical ability subject passed through all of activity in horizontal mathematization. The high mathematical ability subject also passed through all of activity in vertical mathematization.