The author describes a Piaget based curriculum involving three main themes (classification, number measurement/space, and seriation) for young mentally retarded children. Students solve problems by doing something physically and mentally to the data, shuffling the facts about in their minds, so that they will come to a logical solution. Language is used in the program to support the mental operations so that as a child is being trained in a particular mental operation, the teacher models the appropriate language structures. (SBH)