Dyscalculia is one of the barriers to learning for students with some special mental retardation needs. Students with intellectual disabilities may also have dyscalculia. In that sense, in learning mathematics, it is necessary to use various learning media. Related to this condition, the present study aims to determine the effect of the use of instructional video media to introduce natural numbers to students who experience mental retardation with dyscalculia. This type of research is an experimental research design with a single subject. This single-subject research uses the A - B method. The research subjects were chosen based on a purposive sampling technique because the researchers had to find subjects with mental retardation as well as dyscalculia characteristics with these characteristics one elementary special school in Yogyakarta was found. Data collection techniques involved using the method of observation, interviews to determine the characteristics of the subject, tests to determine the ability of subjects to recognize natural numbers. The results of this study indicate that interactive media positively influences the ability to recognize natural numbers in mentally retarded children with dyscalculia. This can be seen from the average score obtained by the subjects before being given an intervention that is 30 and increased to 54 after being given an intervention.