This textbook presents an arithmetic course that seeks to adapt the subject matter to the experiences, interests, and immediate needs of children, and to provide means for a mastery of the formal phases of arithmetic through more scientifically organized drills. This series consists of three books: Primary (ED622333), Intermediate, and Advanced (ED622335). The Primary book contains the work suggested for the second, third, and fourth grades; the Intermediate, the work for the fifth and sixth grades; and the Advanced, the work for the seventh and eighth grades. The text uses only problems that deal with the experiences of children. They deal with their chief occupation -- play, with their constructive activities, with phases of the home and the local community life with which they come into direct contact. Motivated drills, for the mastery of the tables and formal processes of arithmetic, have been systematically and plentifully provided throughout, and should prove a strong feature.