This text was written in response to the recommendations of A Call to Change, and the vision of the NCTM Standards. Its goals are to present important, challenging mathematics relevant to a Standards-based K-8 curriculum, and to prepare prospective elementary teachers to implement the Standards in their own classrooms. Students acquire an understanding of mathematics that is considerably broader than that which they will be required to teach. They develop number sense, spatial sense, and mathematical intuition, and are able to explain mathematical concepts, relationships, and processes, clearly and correctly. This text helps the future teacher to see elementary school mathematics as a "Big Picture, " in which important, interconnected ideas are developed and applied from K through 8. They learn from experience that mathematical understanding begins with concrete models, and then progresses through verbal, numerical, and, finally, abstract stages. As a result, they become confident, successful problem-solvers, and develop an appreciation for the power and beauty of mathematics, and an enthusiasm for teaching it.