Items on Grade K-8 CCSS Math are written to address all domains and each cluster…and in Grades 3-5, to align with individual standards.
Keep in mind these are fundamental skills tests. And so, reporting scores at the standard, cluster, or domain level would decrease the reliability of those score estimates because they would be based on too few items to give a reliable estimate of student performance. Therefore, we report total raw scores and percentiles across the domains, clusters, and standards.
Across the benchmarks and progress-monitoring on the K-8 CCSS measure, items are balanced across CCSS domains, with approximately 2-4 items per CCSS standard. We recently created a secure read-only Google spreadsheet that show standards alignment by test form and item. This Google spreadsheet offer standards alignment information in a format that is much easier to digest/use (i.e., rather than teachers having to go into multiple tech reports and scroll to Appendices tables based on grade).
Here is that Google Sheet: