Examination of secondary school 7th grade students'concept images regarding algebrary expressions and equations with a first degree unknown

The aim of this research is to examine the concept images of the 7th grade secondary school students regarding algebraic expressions and first-degree equations with one unknown. The research was carried out with 71 students studying in the 7th grade of a public school in the Marmara Region in the 2020-2021 academic year. A mixed method research, in which both qualitative and quantitative data can be collected, was used in the research. In order to determine the concept images of secondary school 7th grade students about algebraic expressions and equations with one unknown of the first degree, a two-part "7. Class Algebraic Expression and Equation Concept Image Test" developed by the researcher was used. In the first part of the concept image test, students were asked to define the concepts of algebraic expression and first-degree equation with one unknown and to give an example of these concepts, and the students' images of these concepts were determined. In the second part of the concept image test, the students were given mixed examples of algebraic expressions and first-degree equations with one unknown, and they were asked to choose whether these examples belonged to an algebraic expression or an equation with a first- degree unknown, depending on their level of certainty. In addition, in the second part of the concept image test, students were asked to write down the reasons for their choices, and it was aimed to determine which image they made this choice. After the application, a continuous comparative analysis was made of the data and the concept images of the students were determined in the light of Tall and Vinner's (1981) concept definition-concept image theoretical framework. As a result of the analysis, it was seen that the definitions of the concept of algebraic expression were gathered under the categories of "Operation containing at least one unknown", "Unknown/Letter", "Unknown and number" and "Unknown and equality". In addition, it was observed that some students gave correct examples of the concept of algebraic expression, even if they did not make a definition. In the other dimension of the research, "Finding the Unknown","Unknown/Letter" and "An Unknown" categories were obtained from the students' concept definitions regarding the first-degree equation with one unknown. Similar to the result obtained in the concept of algebraic expression, it was observed that some of the students gave correct examples even if they did not define the concept of first-order equation with one unknown. As a result of the research, it was determined that the students used the concepts of algebraic expression and first-degree equation with one unknown interchangeably. On the other hand, it was observed that the students did not realize the meaning of the equal symbol in the concept of equations and ignored the concepts of first degree, an unknown. Key Words: Algebraic Expression, Term, Concept Definition, Concept İmage