This edition places emphasis on the use of models and diagrams for providing insights into mathematical concepts before generalizations. Although it focuses primarily on teaching content, the extensive use of models and diagrams accomplishes three objectives: (1) assists college students in understanding mathematics concepts; (2) helps students connect and remember ideas and concepts; (3) provides ideas and models for teaching mathematics to elementary school children. The following features help to accomplish these objectives.

Math Activities Preceding each section of the text is a one-page math activity related to the content of the section. A manipulative kit of colored card stock materials is available for the activities and can be ordered with each text at no extra charge.

Investigations At the end of each of the 34 sections of the text there is a reference to either a Computer Investigation, Calculator Investigation, or Laboratory Investigation on the text web site. These Investigations involve the mathematical content of the section and pose open-ended questions that require collecting data, looking for patterns, and forming and verifying conjectures. The Mathematics Investigator software which may be downloaded from the web site is designed to collect data for 14 of these investigations.

Problem Solving Applications Each section of the text contains one or more Problem-Solving Application, which applies the subject matter of the section and is analyzed with Polya's four-step plan.

Problem Openers Each section of the text begins with a Problem Opener related to the content of the section. The solution to each Problem Opener and the problem-solving strategies required is contained in the Instructor's Manual. The Manual also includes one or more ideas for looking back and extending each Problem Opener.

Word Problems and Problem Solving Each set of Exercises and Problems contains a special subsection, Word Problems and Problem Solving.

Problem Solving Strategies Chapter 1 contains eight problem solving strategies and several more are introduced in the remaining chapters.

Puzzlers The text contains over forty mathematics puzzlers. Most occur at the end of the Exercises and Problems and are marked by an icon. Answers for the puzzlers are in the Answer Section at the back of the text.

Historical Highlights Highlights in mathematical history appear throughout the text to suggest the origins of important ideas and provide background on the lives of some of the world's greatest mathematicians.

Visual Models Mathematical concepts usually are illustrated by diagrams and geometric figures before mathematical terminology and abstractions are introduced.

Mental Calculating and Estimating The chapters on whole numbers, integers, rational numbers, and real numbers contain mental calculating and estimating techniques. The exercises involving mental calculating and estimating techniques are marked by an icon.