ABSTRACT
Hearing impairment can effect many educational abilities and will lead in a dealy in his growth. The objective of this research was to study the effect of hearing impairment on mathematical skill of hearing-impaired students of 4th grade of elementary in contrast with normal hearing students. The project was cross-sectional and the tool used was the international standard booklet of mathematical questions. There has been 35 hearing-impaired students with range of moderately sever profound hearing loss selected from the 4th grade of elementary from exceptional schools in Ray, Pakdasht and Varamina, Iran, and 35 normal-hearing students were randomly selected from ordinary schools next to exceptional schools. By analyzing the outcomes, the normal-hearing students showed a better result in knowing, application, argument in aspects of cognitive in contrast with hearing-impaired students and there has been a meaningful difference [p<0.05]. There was not a meaningful difference in mathematical skill between Ray, Pakdasht and Varamina, Iran in hearing-impaired and normal-hearing groups. The hearing impairment effects learing of mathematical skill. It is important for hearing impaired students to presentation various methods in instruction in progress deductive thought and cognitive structure and also development in concepts understand in mathematical domain in rehabilitation services.