Classroom Challenges, developed by the Mathematics Assessment Project (MARS), include both problem-solving and content development formative assessment lessons. Here you can access lesson plans, student materials, PowerPoint slides, and other resource materials to facilitate the implementation of the Classroom Challenges in support of the Common Core State Standards
Inside Mathematics, is a professional resource for educators passionate about improving students' mathematics learning and performance. This site features classroom examples of innovative teaching methods and insights into student learning, tools for mathematics instruction that teachers can use immediately, and video tours of the ideas and materials on the site.
Illustrating the Standards for Mathematical Practice
This site includes NCSM developed materials and resources, work undertaken in collaboration with other organizations, and participating in conferences and other initiatives that promote shared understanding of the CCSS.