Mathematical Representation of Cerebral Palsy Students in Constructing the Concept of Plane Geometry Based on APOS Theory

Abstract

Mathematical representation is needed in conceptual understanding, solving mathematical problems, and communicating mathematical ideas by students. This research describes the form of Cerebral Palsy students' mathematical representation which appear when solving a problem related to the concept of plane geometry. The emerging representation consists of four stages of mental construction namely action, process, object and scheme (APOS). Student work is influenced by physical and psychological conditions in which Cerebral Palsy has limitations in writing, speaking, or performing other acts in the learning process. The work result of the students studied, it appears that there are 3 types form of representation used, they are verbal representation, representation of mathematical expression, and visual representation. In verbal representations, there are complete mental constructs, namely actions, processes, objects and schemes. In the representation of mathematical expressions, and visual representations, mental construction only reaches the object stage. Stage action, the subject mentions what is known and asked from the question. Process stage, shows the ability of the subject to explain the way used in solving the plane geometry problem. Stage object, subject using verbal representation, visual as well as mathematical expression. The scheme stage, the subject associates the multiplication concept with the plane geometry area.