Through KenKen puzzles, students can explore parity, counting, subsets, and various problem-solving strategies.
Using KenKen to Build Reasoning Skills
Harold B. Reiter, John Thornton, and G. Patrick Vennebush
Proofs without Words: A Visual Application of Reasoning and Proof
Carol J. Bell
Reasoning and Proof is one of the process standards set forth in NCTM's principles and standards for school mathematics (2000).