In looking at the subjects’ solutions to the problems with unknowns (see Table 4), students seemed to make more operational mistakes when comparing their solutions to the questions without unknowns. Performance dropped by an average of about 12 percent. It could be said that students perceived this type of question to be more difficult to utilize regular algorithm, so they made more operational mistakes. As with the findings of the majority of the studies listed above, an average of about 31 percent of students thought that the answer must come after the equal symbol. For example, in the question 6 + 7 = [ ] + 4, students thought that 13 must go inside the box. Only an average of about 56 percent of the students was able to give the correct answer to this type of question. When considering the problem’s difficulties, and the grade level of students, this percentage seems very low and concerning. It is very important seeing that even middle