ON DEVELOPING INSTRUCTION MATERIALS IN INCULCATING SECONDARY STUDENTS' MATHEMATICAL REASONING SKILLS

Learning Mathematics with understanding is essential. Grasping it absolutely needs reasoning for every conclusion drawn, one draw it deductively. Many report either formerly or recently revealed the lack of upper secondary students' mathematical reasoning skills (MRS). Concerning this case, the paper reports some results of a research aimed to develop instruction materials, which is designed based on problem-based learning to inculcate upper secondary students' MRS. The materials consist of students' book, work sheet, and instrument to measure the intended skills. The development followed the 4-D model. Three expert validators judged the materials are valid with slight revision. By trials, teachers and students considered it feasible to conduct in classroom. Test on MRS showed a low increasing in students' achievement. It concluded than that the materials developed is effective to inculcate students' MRS.