The following pages illustrate the development of proof in the CPM Geometry course. Students are regularly required to explain the logic of their answers and to support their work with reference to definitions, axioms, and theorems. Most of the first semester is spent investigating basic ideas and developing conjectures. Specific work with proof begins in Unit 2 where students solve logic puzzles that require deductive reasoning in their solutions.
Equal emphasis is placed on writing a logical presentation of the solution.
Students practice justifying solutions in problems with lines, angles, and triangles in units 3-5. Students practice proof with congruence and properties of figures in the second half of the course as well as do proofs with the ideas presented in each of these units. Answers appear in bold print, as they do in the teacher version of the text. Proof problems are identified by the domino icon. This game is the number version of the commercially available logic game called Master Mind.