THE INFLUENCE OF THREE STAGE FISHBOWL DECISION LEARNING METHOD ON MATHEMATICAL LEARNING ABILITY By : Tua Halomoan Harahap, M.Pd (1) Asrar Aspia Manurung.,M.Pd (2) , tuaholomoan@umsu.ac.id Abstract : This study aims to determine the effect of the application of the Three Stage Fishbowl Decision learning method to the ability to learn mathematics in students of SMK Muhammadiyah 9 Medan and how significant the Three Stage Fishbowl Decision learning method affects the mathematics learning ability of students of SMK Muhammadiyah 9 MedanT.P 2016/2017 . The research instrument used was a test in the form of awa l test (pretest) and final test (post-test) consisting of 5 items each of the initial test (pretest) and 5 items of the final test (post-test). The validity test results of 15 item items obtained were 11 valid item items and 4 invalid item items. As the population of this study all students of class XI of SMK Muhammadiyah 9 Medan totaled 93 students, so the sample in this study was class XI TKR which numbered 68 students. The reliability test results of 15 valid obtained that 11 questions were reliable. After raining data the mathematical understanding ability was found to be tcount> ttable, thitung (5.34)> ttable (1.99656). Then Hα is accepted and H0 is rejected. So it can be concluded from the hypothesis test that students' mathematics learning ability in the experimental class is better than the control class. This means that there is an influence between the Three Stage Fishbowl Decision learning method on the ability to learn mathematics in students of SMK Muhammadiyah 9 Medan T.P 2016/2017. The magnitude of the influence of Three Stage Fishbowl Decision learning methods on the ability to learn mathematics cubes and blocks in class XI students of SMK Muhammadiyah 9 Medan T.P 2016/2017 is 2.89%. Keywords: The Effect of Using Three Stage Fishbowl Decision Learning Methods Against Mathematics Learning Ability PRELIMINARY Mathematics lessons are there and studied, starting from Elementary School to Higher Education level, both globally and specifically. Even at the preschool level, mathematics has begun to be introduced, but mathematics has become a frightening specter and is a difficult subject for students in general. Low student learning ability is caused by many factors. One of them is the factor of students where their activity is low (accustomed to being quiet in the learning process) and their initial ability is also low in terms of the students' national exam scores when they first enter school. The teacher factor also influences because it is normal to use teacher-centered learning so that students only listen. In essence, learning is the process of finding, finding and seeing the main problem. Learning is also said as an effort to solve the problem or problem at hand. This is directly related to the ability that must be possessed in the standard mathematics learning process (mathematical processes) as stated by Bahrul and Yusuf (2011: 214) that mathematics is one of learning involving several