The problem of school failure remains one of the pressing problems of modern pedagogy and psychology. The monograph presents a cultural approach to the analysis of the organization of study and training of one of the largest groups among underachieving schoolchildren - children with mental retardation. The work presents clinical, psychological and pedagogical characteristics of children in this category, shows the features of their acquisition of reading and mathematical knowledge and skills by years of study in primary school. The monograph is addressed to researchers, university teachers, students of pedagogical, psychological, defectology faculties, specialists in the correctional system. developmental education.