standard_description: Prove theorems about parallelograms. Theorems include: opposite sides are congruent, opposite angles are congruent, the diagonals of a parallelogram bisect each other, and conversely, rectangles are parallelograms with congruent diagonals.
problem_activity: Stage 1: Explore
Required Preparation
Materials to Gather
Picture books

Narrative
Students look at picture books and identify groups of objects. They may recognize small quantities or count to figure out how many.
Additional Information
Each group of 2 needs at least one picture book that shows groups with different numbers of objects throughout the book.


aligns: no