The present study was conducted to compare the performances of high-achieving sixth grade students on written computation, symbolic representation, and pictorial representation tests. The study enrolled 107 sixth-grade students in three schools. Data were analyzed by using the Kruskal Wallis and Mann Whitney-U Tests and interviews were conducted with six students. The Mann Whitney U test was utilized to explore the groups that were favored by the difference. Student performances were lower particularly in the pictorial representation test than the other two. It is interesting that the students with mathematics grade average points of 4 and 5 at the end of the first academic term failed to show the same success that they showed in the written computation test in the two other tests as well. Therefore, it can be said that the teachers evaluate the students who are good at doing operations as successful in mathematics.