Sometimes looking at implementing the Common Core standards appears as a daunting task! "There's so much for students to learn!" "How can I possibly do this?" "How can I prioritize these things?"
Achievethecore has put together a great tool that identifies the shifts in Common Core mathematics standards and the Major Clusters, Additional Clusters and Supporting Clusters for grades K-8. Check out this great resource on achievethecore.org @ http://achievethecore.org/content/upload/Focus%20in%20Math_091013_FINAL.pdf