One in a series of core instructional materials for apprentices to use during the first or second years of apprenticeship-related subjects training, this booklet deals with basic mathematics. The first section consists of an outline of the content and scope of the core materials as well as a self-assessment pretest. Covered in the three instructional chapters included in the booklet are arithmetic operations (characteristics of numbers and addition, subtraction, multiplication, and division); fractions (fractions as parts of a whole; adding, subtracting, multiplying, and dividing fractions; decimal fractions; adding, subtracting, multiplying, and dividing decimal fractions; and using percentages); and formulas and tables (writing formulas for rules and solving formulas for unknowns as well as reading tables). Each chapter contains an overview, a chapter example, and a self-test exercise. Appended to the booklet are answers to the self-assessment pretest, answers to the self-assessment exercises, a posttest, and answers to the posttest. (MN)