(4) Solution in symbolic representation
The students adapting symbolic representation can comply with substituting and estimating strategies to solve problem (See Figures 9.1, 9.2, 9.3). These students have already figured out the relationship among variables and can operate to control it. While it is different form the former presentations, they adapted symbolic method to induce and represent the relationship of variables. They demonstrated the change between two variables by putting the equation side by side. This method is not as complex like former representations. If you substitute the appropriate number to get the right answer, then you can solve the problem. From the student performance, we can realize the difference about their problem-solving strategies.