<![CDATA[Students' ability to understand mathematical concepts in the quadratic function material is still low because students have difficulty in connecting algebraic forms with graphical representations. as well as apply draft in solution problem. Besides That, learning Which still centered on Teacher And lack of utilization technology cause student not enough active in building conceptual understanding. This study aims to determine the differences in mathematical concept understanding abilities of students who learn using the Problem Based Learning model assisted by GeoGebra and Kahoot , as well as to describe the feasibility of the media and test instruments used. The results of the learning media validation obtained an average percentage of 82.00% with category very valid , whereas validation instrument test get an average of 98.33% with a very valid category . The trial results show that the GeoGebra-assisted PBL class get mark average pre-test 54.20, post-test 84.60, And N-Gain 0.66, while the class Problem Based Learning assisted Kahoot get mark average pre-test 53.80, post-test 79.20, and N-Gain 0.55. Thus, the media and instruments used are suitable for application in learning, and there are differences in the ability to understand mathematical concepts. student between second model learning, where is the problem Based Learning GeoGebra assistance is more effective in improving students' mathematical concept understanding abilities in quadratic function material.]]>
