Peningkatan Kemampuan Penalaran Matematika Siswa Melalui Pembelajaran Open Ended (PTK Pembelajaran Matematika Kelas VIII SMP N 2 Gatak)

The purpose of this research to describe the improvement of student’s mathematical reasoning abilities through Open Ended learning.This type of research is the research action class (PTK). Data collection techniques using observations, field notes, tests, documentation. Data analysis using the techniques of data collection, data reduction, data presentation, and draw conclusions. The results showed an increase the ability of student mathematical reasoning with indicators many students are able: 1.)submitted hypothesis before the completion of the action of 32,5% and after the action of 65,63%. 2.)make a manipulation of mathematics before the completion of the action of 25,5% and after the action of 65,63%. 3.)collect the conclusion,arrange the evidence, give a reason or evidence toward solutions before the completion of the action of 25% and after the action of 65,63%.4.)collect the conclusion from the statements before the completion of the action of 30% and after the action of 50%. 5.)check the corrections of the argument before the completion of the action of 23% and after the action of 62,5%