The document discusses the benefits and characteristics of using workbooks in mathematics classrooms. It notes that workbooks save students time by eliminating the need to recopy problems from textbooks, and allow for easier grading of student work. An effective workbook provides a variety of exercises at different levels of difficulty to accommodate different learners. It also describes some key characteristics of workbooks, such as being written by experienced teachers, providing space for working problems, and including answer keys. Overall, the document examines how workbooks can serve as useful supplementary materials for reinforcing mathematical concepts introduced in core textbooks.