K-2
3-5
Geometry and spatial sense are fundamental components of mathematics learning. They offer ways to interpret and reflect on our physical environment and can serve as tools for the study of other topics in mathematics and science.
Geometry is a natural area of mathematics for the development of students’ reasoning and justification skills that build across the grades. As the study of the relationships among shapes and their properties becomes more abstract, students should come to understand the role of definitions and theorems and be able to construct their own proofs.
Principles and Standards calls for geometry to be learned using concrete models, drawings, and computer software. With appropriate activities and tools and with teacher support, students can make and explore conjectures about geometry and reason carefully about geometric ideas. (Principles and Standards for School Mathematics: An Overview, NCTM)