This activity aligns with Common Core standards:
5.OA.2 Write simple expressions that record calculations with numbers, and interpret numerical expressions without evaluating them.
5.G.3 Understand that attributes belonging to a category of two dimensional figures also belong to all subcategories of that category.
It addresses the following mathematical practices:
- Model with mathematics.
- Use appropriate tools strategically.
- Attend to precision.
- Look for and make use of structure.
In this investigation, students work together in groups and use colored connecting cubes to determine this rule on their own. By investigating various combinations of side lengths, and writing the results in equation form, students are practicing algebra skills while forming conclusions about the ways triangles can be formed. Guiding questions at the end provide scaffolded support for students who require it. This activity works well as a math station/center.
Tip: When forming triangles out of the connecting cubes, show students that only the edges of the rods should connect in order to maintain accurate results.