Improving Reasoning Ability of Elementary Students in Solving Mathematical Problems With The OSCAR Learning Model

This study aims to describe the increase in Elementary School students' reasoning ability in solving mathematical problems using the OSCAR learning model and responses students. The OSCAR model was developed by researchers in 2017. The OSCAR model based on the Problem Based Learning (PBL) model and several learning approaches such as Realistic Mathematics Education (RME) and Contextual Teaching and Learning (CTL). The difference between OSCAR and PBL lies in the Self-observation phase. This phase gives students the opportunity to observe problems individually before being discussed in groups. This model consists of five phases, namely Orientation, Self-observation, Construction, Association, and Reflection. The research used quasi experimental method with the one group pretest-posttest design. The instrument that used are mathematical problem solving test and student response questionnaire. The subject of this research is the V-B grade students of SDN Sidotopo Wetan I Surabaya in 2017/ 2018. To see the increase in student reasoning ability is to calculate the Ngain index. The calculation result of the N-gain reasoning score has an average 0,40. This shows an increase. The results of the analysis on students' responses showed an average of 99,66% of students happy about the subject matter, work-sheet, exercises, and how teachers teach.