The United States must restructure mathematics education—both what is learned and the way it is taught—if children are to develop the mathematical knowledge and skills they will need to be personally and professionally competent in the twenty-first century. Joining the recent reports that have opened a national dialogue on these issues, Reshaping School Mathematics focuses discussion on essential ideas that transcend details of current curricula or assessment results. It examines changing perspectives on the role of mathematics in society and changing practice in the use of technology—particularly calculators and computers—in mathematics education.