Numbers and the operations that we perform with them are the starting points for all mathematics. Accordingly, Principles and Standards for School Mathematics makes the Number and Operations Standard first among the five Content Standards and gives it centrality across the mathematics curriculum from prekindergarten through grade 12. The Navigations Series translates Principles and Standards for School Mathematics into action. Each book includes practical, teacher-tested activities and a supplemental CD-ROM that features applets for students' use and resources for teachers' professional development.
Navigating through number and operations in grades 3-5. Reston, VA: National Council of Teachers of Mathematics; 2007.