SakurSuhermi2014-04-042014-04-042014-04-04wahyu sari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/6032These research aims to increase of student’s ability to criticals think. Research Desain is Classroom Action Research with one cycle. Collected data is data about lecturing execution with observation technic and data about ability of student to criticals think with written tes technique. From three session of lecturing executed, is observed that student work in finishing problems have walked better. During execution three sessions lecturing becoming resistance is prepare result of group discussion to presentation. Skill of student use laptop in preparing report result of team-work still weakens. Obtained conclusion that “If the learning strategy of Problem Solving used in lecturing betterly can improve student's ability to criticals think in items of partial defferential application of function two variables on Advanced Calculus CoursesenUR-Scientific Work Lecturer