Senior high school mathematics learning device development based on guided discovery to improve students' reasoning ability (preliminary research)

Students' mathematical reasoning ability that can be found in the field has optimal yet, this can be seen from school learning, and teacher has yet got the students to get used to solve the mathematical reasoning questions. The purpose of this research is to produce mathematics learning device based on guided discovery to improve students' reasoning ability. This is a development research. The development model in this research is plomp model which consists of three phases, namely, preliminary research, development or prototyping phase, and assessment phase. The researchers hinge only on preliminary research. The result of the data analysis on this first phase revealed that: 1) the students' reasoning ability is not yet optimal. 2) Some students' still think mathematics is a difficult subject to learn. 3) The development of student worksheet is of vital importance in order to be able to comprehend the learning material. 4) Students expect that student worksheet will discuss problems related with mathematics knowledge in daily life as well as problem related with their individual activity.