This book is designed for teachers in elementary and middle schools who need explanations of problems and questions concerning the metric system and a source of classroom activities to aid in teaching the metric system. The book is divided into three parts. The first part is a primer of information designed to help a teacher in answering the many questions that children and parents will ask. This part also includes practice problems for all teachers involving the mathematics of metrics. The second part consists of ideas and activities that teachers of the nonmathematics curriculum may incorporate into their lessons to aid in the total metric experience of the learner. Included in this part are sections on language arts, reading, social studies, music, and art. The third part deals with classroom activities that teachers of mathematics may use. A special section is included which uses only nonstandard measurement activities designed for primary children. Attention is also given in this section to the use of metric measurements in presenting activities that are concrete, semi-concrete, and abstract in nature. The activities are labeled according to length, weight, area, volume, and temperature. (Author/MP)