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Developing teaching materials two-dimensional figure-based on Palembang local cultural context

Developing teaching materials is important to help students in learning mathematics especially for two-dimensional figure by using Palembang local cultural context. The purpose of the research was to develop whether the teaching materials two-dimensional figure-based on Palembang local cultural context are valid, practical, and have potential effect. The research method used research and development (R&D). The research consists of two stages, namely the preliminary stage and the formative evaluation stage. In one-to-one evaluation involved three students. Then, small group evaluation involved 9 (nine) students in the research. Meanwhile, in field test stage involved 29 students. Data collection techniques employed interviews, tests and documentation. The research was conducted in seventh graders at one of junior high school in Indonesia. The results of this study were the developed teaching materials were categorized as valid, practical and have potential effect. The average score of validity content, construct and product design were 3.65 which was very highly valid level. The practicality of one-to-one was 3.47 and small group evaluation was 3.61 which was at very highly practical level. The teaching materials were categorized as effective. It showed that there were 24 students (82.75%) out of 29 students (17.24%).


Introduction
Curriculum in Indonesia continuously changes result in mathematics learning encountering a few improvements as well as. Mathematics which is initially abstract is created in such a way that it gets to be something concrete. The Curriculum 2013 required that in the teaching and learning activities for all graders and topics accomplish attitude competency, knowledge, and skills, in all learning process [1]. In order to implement the Curriculum 2013, it would require an innovation in the planning learning process and learning approaches especially in learning mathematics. Mathematics is exceptional fundamental subjects to be well understood by students.
The specified situation has relevance to mathematics; since mathematics is abstraction of the real life. Therefore, it is important for students to connect something abstract to be concrete with real life in mathematics courses [2], [3]. Learning mathematics is very important for solving many problems in human life because learning mathematics is very attractive to improve students' ability dealing with mathematics [4]. One of the abstract concepts in learning mathematics is two-dimensional figure. Two dimensional figure was arranged by a collection of points, lines and fields. The two-dimensional figure is divided into two, namely quadrilateral and triangle. This study specifically discusses on quadrilaterals. The sorts of quadrilaterals such as parallelogram, rectangle, square, rhombus, kite and trapezoid are illustrations of concepts, whereas "parallelogram could be a quadrilateral that has two sets of parallel opposite sides," is an illustration of a definition [5].
Teaching materials plays a critical part in improving student learning outcomes. Subsequently, to improve the quality of learning, it is necessary to develop valid, practical, effective and innovative

Experimental Method
The methodology of this research employed research and development (R&D) [14]. To develop valid, practical and have potential effect teaching materials two-dimensional figure based on Palembang local cultural context for junior high school students and to determine potential effects on students in mathematics activity. The study was conducted in two stages phases, namely the the preliminary stage (i.e. preparation and design stages) and the formative evaluation stage (i.e. expert reviews, one-to-one, small group, and field test stages) [15]. At the preparation stage, the researcher decided and dissected the place and subject of study. The researcher moreover surveyed a few of the literary on research development related to this research. Further, the researcher examined the Curriculum 2013 for junior high school associated with the characteristics of RME and teaching materials by utilizing Palembang local cultural context. The researcher also contacted the teachers in the school and inquired the procedure to do research in that school. As regards the prototyping phase, the flow used is formative evaluation, including selfevaluation, expert reviews, one-to-one, small group evaluation, and field tests. The sample of the formative evaluation in Table 1. The formative evaluation design flow described in Figure 2. In the stage of the expert review, the prototype 1 was approved by experts to be observed, assessed and evaluated. Expert Validation used in this study is in terms of content, language, constructs. The results of expert review are used to revise the product; 3) In one-to-one phase, the researcher conducted tests to students individually. The results of one-to-one are utilized to revise the first prototype. The results of expert reviews and one-to-one produced the second prototype of teaching materials; 4) In the small group evaluation phase, the researcher produced prototype 2 through revise by experts. The small group evaluation of the test was used to identify the weaknesses and strengths, effectiveness, efficiency, usability, and the interest of the prototype 2; 5) The prototype 3 was then used for the field tests. The field test was conducted in class VII at one of State Junior High Schools in Palembang. The products produced at the field test must meet the quality criteria which comprise of three criteria: validity, practicality and have a potential effect (effectiveness).
Based on the research method used in this study, methods of collecting data in this study were questionnaires, tests, documentation, and walk-through. The questionnaires to know students' need analysis dealing with the teaching materials. The documentation like videos and photos to record the teaching learning process. Walk-through was used for the revision of the first prototype combined with one-to-one to get the second prototype; interviews were conducted to students after the students finished the lesson. The test was used to determine the potential effects of this study.
The teaching materials based on Palembang local cultural context must be valid, practical and have a potential effect. The validity of the instructional materials may be determined by looking at the results of the validation expert (expert review), the interview phase during one-to-one, and the results of the quantitative analysis of items on the phase of a small group evaluation. Meanwhile, the practicality of teaching materials two-dimensional based on Palembang local cultural context can be noted from the observations and interviews in small groups and interviews on the field test with reference to the practical sense. Finally, the potential effects of teaching materials based on Palembang

Results
Phases of formative evaluation consist of one-to-one, small group evaluation and field test. The oneto-one evaluation consists of three students: students with low, moderate, and high abilities in mathematics. Before formative evaluation, the researcher validated the teaching materials which are based on Palembang local cultural context. The validation of teaching materials related to Palembang local cultural context consists of validation of content, construct and product design by the experts, as shown in Tables 1, 2 and 3.  Table 1 describes the recapitulation of content validity from questionnaires comprising fifteen questions, in which the researcher acquires the average score of content validity was 3.75 which was highly valid level.  Table 2 shows the recapitulation of construct validity from questionnaires consisting of eighteen questions and the researcher acquires the average score of construct validity was 3.52 which was highly valid level.  Table 3 describes the recapitulation of product design from questionnaires consisting of ten questions and the researcher acquires the average score of construct validity was 3.70 which was highly valid level. From table 1, 2 and 3, the researcher acquires the average score of three validities were 3.65. Then, the researcher distributed the questionnaires in one-to-one and small group evaluation to discover the practicality of the teaching materials, as demonstrated in Table 4 and Table  5. Table 5 describes the result of questionnaire in small group evaluation from questionnaires comprising fifteen questions, in which the researcher acquires the average score of practicality was 3.61 which was highly practical level.

Discussion
This research has developed teaching materials which are based on Palembang local cultural context in the form of Student Activity Sheets (LAS), namely mathematics instructional materials with the topic of two-dimensional figure. LAS begins with understanding the concepts and principles of twodimensional figure based on Palembang local cultural context.
At the end of LAS, there are questions to practice concepts understanding. In accordance with the research objectives, the teaching materials developed have potential effects on the scientific activities of students in the learning process. Highly visible activity is the activity of observation, reasoning, ask questions, and try to do the working group in Student Activity Sheets (LAS). The following photos show the activities of students in LAS work in groups in Figure 3.  Figure 3. Students observing the stairs in a mall Figure 3 could be seen that the students work in group solving problems in LAS. In these activities, based on the observation, the students made observations and analyzed the characteristics of parallelogram. In addition, the students conducted reasoning when she/he compose a report on the student worksheet.  The student's work shows the activities of the reasoning process. This study is limited to the product development process of teaching material of two-dimensional figure. The product of this research is the teaching materials in the form of student activity sheet (LAS) which has been thought the process of developing appropriate with research methods.
The development of teaching materials is adapted to the demands of the learning in the Curriculum in 2013 based on scientific approach: in the learning process the students must do observation, reasoning, trying, asking, and communicating. This approach is in accordance with the process of oriented learning on problem solving question problems by using local cultural context with RME approach.
In conclusion, based on the experiment in seventh graders at one of junior high schools, it is shown that the RME approach by using local cultural context in developing teaching materials twodimensional topic. The students were very active and enjoyed learning. It can be underlined that students were effectively within the learning process and developed or constructed the concept of learning through observing, trying, asking, reasoning, and communicating about two-dimensional figure particularly quadrilaterals.

Conclusion
Based on the results and discussions, it can be concluded that the teaching materials based on Palembang local cultural context which are developed, in the topic of two-dimensional figure, is in accordance with the characteristics of the curriculum 2013 by utilizing RME approach. Furthermore, based on the research results, it is recommended that teachers can use this teaching learning materials, because it is in accordance with the characteristics of the Curriculum 2013 and RME approach by using local cultural context. Since this study is restricted to the usage, it is suggested that other researchers may conduct research on the students' learning outcomes.