The "Curriculum and Evaluation Standards for School Mathematics" (1989) provides a vision and a framework for revising and strengthening the K-12 mathematics curriculum in North American schools and for evaluating both the mathematics curriculum and students' progress. The document not only addresses what mathematics students should learn but also how they should learn it. When completed it is expected that the Addenda Series will consist of 22 supporting books designed to interpret and illustrate how the vision could be translated into classroom practices. Targeted at mathematics instruction in grades K-6, 5-8, and 9-12, the themes of problem solving, reasoning, communication, and connections are woven throughout the materials, as is the view of assessment as a means of guiding instruction. Activities have been field tested by teachers to ensure that they reflect the realities of today's classrooms. Building on the experiences of the elementary grades, the "Patterns in Functions" booklet in the Grades 5-8 series provides examples of how patterns can be used to develop or deepen understandings of important concepts in exponents, number theory, rational numbers, measurement, geometry, probability, and functions. Each of the guide's five sections starts with problems to explore, (called investigations), in which patterns can be used to analyze and solve the problem. This method of using patterns to investigate problem situations allows students to think before and beyond the answer: to see patterns, to generalize, to extend, to connect, and to evaluate. The five sections are: (1) Exponents and Growth Patterns; (2) Number Theory and Counting Patterns; (3) Rational Number Patterns; (4) Measurement and Geometric Patterns; and (5) Graphs and Functions as Patterns. (MDH)