The purpose of this study was to analyze the ninth graders' structure sense displayed in solving quadratic equations by measuring their ability to recognize an equation as a structure and to suggest effective strategies for teaching and learning algeb...
The purpose of this study was to analyze the ninth graders' structure sense displayed in solving quadratic equations by measuring their ability to recognize an equation as a structure and to suggest effective strategies for teaching and learning algebra.
The questions for this research were as follows;
1. Depending on the structures of quadratic equations, what differences are made in the ninth graders' ability to solve quadratic equations?
2. What differences in their structure senses are observed during the process of solving quadratic equations and what are the causes of these differences?
A group of 198 ninth graders in Y middle school(located in Guro-gu, Seoul) were asked to take a quadratic equation structure sense test. Out of 198, 15 test results were excluded because they were either left blank or had irrelevant answers to the test questions. The individual interviews with 4 students in need of in-depth analysis were conducted as well.
The quadratic equations on the test were divided into the 5 following structures([A]aχ²+bχ=0, [B]χ²±2aχ+a²=0, [C]χ²-a²=0, [D]acχ², [E]χ²=k), and each structure was classified into 3 types.
When solving each type of equations, students can:
● recognize a familiar structure in its simplest form.(type 1)
● deal with a compound term(power) as a single entity or choose appropriate manipulations(multiplications and divisions) to make best use of a structure.(type 2)
● deal with a compound term(sum) as a single entity and through an appropriate substitution recognize a familiar structure in a more complex form.(type 3)
The results were as follows;
First, as for the equations to which factorization formulas cannot be applied, the percentage of correct answers was relatively low. Of all the equations, the ones to be solved by factoring(structure [A]) were answered incorrectly by the highest percentage of the students. The response rate on the ones to be solved by square root(structure [E]) was relatively low. Many students solved the equations by expanding them, but failed to deal with a compound term(sum) as a single entity.
Second, when solving an equation, each student displayed different structure sense, upon which their problem-solving abilities varied. Students who showed a tendency to stick to a particular method regardless of the structures of equations failed to solve unfamiliar types of questions which cannot be solved with that particular method.
The results lead to the following conclusions;
First, students need to be exposed to a variety of range of equations which enable them to acquire a proficiency in using various formulas such as square root, perfect square, quadratic formula as well as factorization.
Second, students made a lot of mistakes while opening brackets, unable to recognize the structures. We should encourage students to identify equations not as an object of simple manipulation but as a structure.
Third, it is crucial that students realize each structure has its best solution through the experiences of tackling an equation repeatedly using different formulas and manipulations.
Lastly, in light of the fact that students got the wrong answers when using previously learned mathematical concepts such as the quality of equation and the definition of square root without fully comprehending the concepts, it is evident that we should facilitate students to solve equations with the basic concepts clearly understood.