Students’ perception of letters as specific unknown and variable: The Case of Iran

The purpose of this study was to assess student’s understanding variable concept. In respect thechanges math curriculum in Iran, especially way that introduced the new textbook,it is necessary students’ involving these approaches. Thepresent followed an explanatory sequential mixed method design. subjects studywere 7th, 8th and 9th grade students living different area Tehran city. Data collected from awritten test semi structured interviews. Our sample 400 students. Interviews conducted with15out them. By analysing data textbook based on Kuchemann’(1981) Sfard’s(1991)theories, with such training were not recognizing role situationand often see it as specific unknown. They also made mistakes for simplifying algebraic expressionand they tried get solution by joining numbers letters.