In this study, the integral subject in which difficulties mostly seen about learning and understanding in mathematics education has been studied. The aim of this study is to determine that primary (secondary) preservice mathematics teachers' performance in given tests about the integral problems' having same numerical solution but different presentation forms and to find out the causes of the failures in these tests. The mixed method, enriched with regards to quantitative and qualitative datas, has been used. When the preservice teachers' answers given to the these tests were analyzed, it has been found out their performances differentiate in interclasses and in the same class group. Besides the preservice mathematics teachers have become successful in tests which have been comprising of symbolic, visual and verbal problems respectively. The preservice teachers have explained their opinions about the reasons of their failures in verbal, visual and symbolic tests, and they have been criticised.