Mathematics education in the schools today often looks quite different to parents than what they remember from their past schooling. Emphasis has shifted away from pencil/paper arithmetic and drill, to mental arithmetic and a deep understanding of number and operation as a foundation for algebra. As a result of new standards, children today are expected to write mathematical arguments, choose appropriate models, analyze patterns, and solve problems. Some parents may be skeptical of the changes and create difficulties for schools trying to reform. Pressure from these parents who are upset may lead a school to abandon reform efforts to meet the new standards. Other parents are supportive of the changes but often feel inadequately prepared to help their children at home. Many even suffer from math anxiety. This book is designed to provide information to parents about the changes and why they have come about. Secondly, it provides much information about what parents can do at home to help their children be successful, including a section on mental computation and its importance in today's world dominated by handheld digital devices. The book and related DVD can also be beneficial to the home schooling market. This book is a Spanish translation of a previously published version in English.