The intent of the Common Core State Standards is mastery of grade-level content by the end of the school year by building a solid foundation. Major Clusters, seen repeated within trimesters, require greater emphasis than others based on the depth of the ideas, the time that it takes to master, and/or their importance to future mathematics. In addition, an intense focus on the most critical material at each grade level allows depth in learning which is developed through rich mathematical experiences as described by the Standards for Mathematical Practice. Supporting Clusters provide opportunities for students to go deeper within the content and experience it in new situations. Focusing only on the content of the Major Clusters and disregarding the importance of the content of the Supporting Clusters leaves students without the knowledge necessary to build concepts through the grades. “To say that some things have greater emphasis is not to say that anything in the standards can safely be neglected in instruction. Neglecting material will leave gaps in student skill and understanding and may leave students unprepared for the challenges of a later grade.” (Jason Zimba, 2011)
The Standards should not be taught in isolation. Due to connections between and among standards and domains, teachers are encouraged to integrate, where applicable, related standards within their instruction. For example, a comprehensive mathematics lesson might include content from the Operations and Algebraic Thinking and Measurement and Data Domains. Organizing curriculum in this manner fosters a coherent curriculum; one in which each standard is not a new event, but an extension of previous learning across grade levels and within grade level clusters. It is important to note that the order in which the Standards appear within each trimester does not necessarily indicate the order in which they must be taught.