Mathematics and the use of mathematical thinking should be much more than what has been traditional school arithmetic. Much of the mathematical reasoning can be developed and experienced out of school, particularly in the home. This material is a teacher's guide designed to help parents support what is done with their children in class. Background material for parents is provided. End-of-the-year assessment material is presented. A total of 29 activities on the following concepts and skills are included: (1) equality and inequality; (2) use of operations; (3) place value; (4) computation; (5) geometry; (6) logic; (7) ratio; (8) use of calculators; and (9) use of LOGO. (YP)