This is an SMSG elementary school text for first-grade students. The development of mathematical ideas in the text is grounded in appropriate experiences with things from the physical world and the immediate environment. Chapter topics include: (1) sets and numbers; (2) numerals and the number line; (3) sets of ten; (4) introduction to addition and subtraction; (5) recognizing geometric figures; (6) place value and numeration; and (7) arrays and multiplication. (MP)