The purpose of this study was to compare the differences in recognition to contents of practical knowledge in math for students with intellectual disabilities between special school teachers and special class teachers. The special school and special class teachers were teaching students with intellectual disabilities, on various levels, that included elementary, middle and high school level students. Two-hundred special school teachers and two-hundred special class teachers participated in this study and we utilized the following: the t/F tests, one way ANOVA, correlation analysis, and multiple regression analysis. As a result, we compiled our results and findings, and put them in summary form. We first begin with special school teachers, who indicated statistical differences in the content of practical knowledge and mathematics, based on special education career factors. The special school teachers recognized that the most important content, for learners to grasp, the practical knowledge of mathematics. The sub factors of special school teachers’ practical knowledge in mathematics were found to exhibit a high degree of statistical correlation. Second, special class teachers indicated statistical differences in the contents of practical knowledge of math, based on special education careers and the levels of school factors. The special class teachers recognized that the most important factor in identifying the knowledge of learners was to measure the contents of practical knowledge in math. The sub factors of special class teachers’ practical knowledge of content in math also exhibits a high degree of statistical correlation. Third, and lastly, the special school and the special class teachers’ perception in regards to the contents of practical knowledge in math were found insignificant.