Classify and Capture: Using Venn Diagrams and Tangrams to Develop Abilities in Mathematical Reasoning and Proof
Mathematics Teaching in the Middle School
National Council of Teachers of Mathematics
This article describes a game of classifying objects according to their attributes using a three-set Venn diagram, then analyzing the classification of the objects to determine their accuracy. Students attempt to capture opponents' game pieces (tangrams) by making mathematical arguments that identify misplaced pieces.
Moyer, P. S., & Bolyard, J. J. (2003). Classify and Capture: Using Venn Diagrams and Tangrams to Develop Abilities in Mathematical Reasoning and Proof. Mathematics Teaching in the Middle School, 8(6), 325-330.