Previous studies showed that students did not understand the concepts of variable (Kuchemann, 1981a; Macgregor& Stacey, 1997). Thus, students tended to make different types of alternative conceptions in the computations of variables. Likewise, the presence of negative integers in an expression led to several types of alternative conceptions(Vlassis, 2002). It is believed that items involving negative integers would induce inappropriate r from the students. Therefore, systematic constructed al expressions items would be able to identify similar kinds of alternative conceptions made by students when simplifying these items.