Common Core State Standards in the middle grades: what's new in the geometry domain and how can teachers support student learning?

The Common Core State Standards for Mathematics (CCSSM) is a primary focus of attention for many stakeholders’
(e.g., teachers, district mathematics leaders, and curriculum developers) intent on improving mathematics education.
This article reports on specific content shifts related to the geometry domain in the middle grades (6–8) mathematics curriculum. The methodology employed allows for comparisons of content across multiple standards documents. We report on some dramatic changes with regards to the geometry content taught in the middle grades. We found 52% of the middle grades geometry CCSSM learning expectations will be new to the respective grade level at which they are taught in at least six of the eight states analyzed in this study (57% in grade 6, 50% in grade 7, and 50% in grade 8).
We also highlight three areas that represent “new” geometry content at the middle grades based on our analysis of CCSSM and pre-CCSSM state standards.