The Modern Arithmetic Curriculum is an outgrowth of various influences which have been operative over a period of years. Some factors have been in the picture for more than thirty years, others are of more recent origin—or are being recognized more recently as having significance. Among the more prominent of these influences are the changing philosophy of education, increased knowledge of child development, clarification of the nature of human learning, a rethinking of the purposes of instruction in arithmetic, and changes in our culture. As a result of these influences arithmetic curriculums are becoming much more realistic about what children need in arithmetic and what seems appropriate and within children's capabilities at various age levels. Considerable research evidence has been accumulated on the nature of the leaming process in arithmetic, the nature and the place of meanings in arithmetic, and upon the comparative value of various methods of instruction. These researches have significance for the teacher and curriculum maker, and although the research is not as complete as is to be desired, every advantage should be taken of the findings thus far in planning sound progress in arithmetic for children of elementary school age.