This document is the teacher's guide for a curriculum designed to teach mathematics in a social studies context. It provides mathematical experiences in real world contexts that help students interpret, experiment, communicate, and look for multiple solutions to complex problems. The curriculum uses mathematics in context to help students develop higher order thinking and communication skills. This approach encourages students to interact with each other and the material. Students begin to see that skills and concepts are part of a connected body of knowledge. The context gives students a reason to learn and remember mathematical skills and shows them how these skills and concepts are applied in actual practice. It shows them that they can use mathematics for learning about the world. This book provides a variety of thematic contexts for mathematical skills and mathematical understanding, including polling, studying trends in census data, and designing a public rail transportation system for Los Angeles. Through these activities students participate in discussions, interpret and analyze data, make decisions, and present their ideas. In the context of thematic applications, students see how otherwise apparently unrelated skills are related. They learn about the interdisciplinary nature of real problems. Each of the two parts of the guide is divided into topical chapters. Each chapter starts with an overview and a list of mathematical concepts, skills, vocabulary, and materials involved in the activities in that chapter. Each activity includes a list of handouts that are located at the end of each chapter. Contains 20 references. (DK)