Methodology
Design of the Study
Students' thinking processes and procedures used in simplifying these items were obtained through their answer scripts and interview transcripts. Students used appropriate or inappropriate concepts in simplifying algebraic expressions. Their underlying concepts were revealed through execution of these procedures. The alternative conceptions made by students were classified according to the types of alternative conceptions and quantified according to their frequencies of occurrence. This classification and quantification of alternative conceptions provided an opportunity for the researcher to discover the possible causes of these alternative conceptions by analyzing in detail the inappropriate concepts being used by the students. Interviews were conducted in order to elicit student justification for the alternative conceptions used in obtaining their solutions. Interviews provided an insight into students' thinking processes that are not usually evident in their working.