1 st SEA-DR PROCEEDING ISBN : 978-602-17465-1-6 406 FIRST CYCLE ON DESIGNING THE TANGRAM GAME ACTIVITIES AS AN INTRODUCTION TO THE CONCEPT OF AREA CONSERVATION Game Activity for 3rd grade (9-10 years old) Shofan Fiangga Surabaya State University shofan.rizvia23@gmail.com Abstract Most of the teachings in the topic of area measurement tend to give the formula too early to the students. This situation results the condition where the teaching of the teacher is not appropriate with what the students understand in their state results what van Hiele called as mismatch situation. The students could not have the meaning of measuring area except remembering formula. This situation should be administered properly by developing a well design learning activities that could help the students to understand area conservation in area measurement. To develop a good local instructional theory, RME theory suggests that we must apply the parts of each constructed among guided reinvention, didactical phenomenology, and emergent modeling well. Here, the model of tangram by using Dzpricedz is developed to reason with the concept of area especially for the big idea of conservation. Then, we expect that it will become the model for reasoning the concepts of area and help them to solve area related problems. The study has been conducting by framing the learning design on the aforementioned as the guideline to develop the local instructional theory. The ongoing analysis on this study suggests that area conservation for 9-10 year-old pupils is a difficult task. They tend to still use mechanistic reasoning than logical reasoning. By what I mean, they have difficulty in reasoning logically using geometrical picture or drawing. Thus, they could use the price and calculate the total as the reasoning (mechanistic approach). However, they have a better performance in doing area conservation using geometrical reasoning when they deal directly with hands-on activity using geometrical figure (tangram puzzle). This finding is also parallel with the first 2 levels development of van Hiele’s level of geometrical reasoning, visualization and Analysis. The ongoing analysis also suggests that the use of scaffolding is important to help the students in measuring an area using the concept of area conservation. Keywords: Area Conservation, Tangram, Van Hiele, Realistic Mathematics Education INTRODUCTION Most of the teachings in the topic of area measurement tend to give the formula too early to the students (e.g. Kordaki & Balomenou, 2006; Kospentaris et al., 2011; Papadopoulos, 2010). This results in the students understanding of area as merely procedural, as the use of the formula. Nevertheless, these studies provide a suggestion of the importance of learning the concept of area conservation in the school curriculum. They agreed with the idea of why we need to focus on conservation as the core in understanding area. Accordingly, the understanding of conservation of area is an Code: P-47