Ohio Mathematics Academic Content Standards (2001)
Mathematical Processes Standard
Benchmarks (5–7)
E.
Use deductive thinking to construct informal arguments to support reasoning and to justify solutions to problems.
Benchmarks (8–10)
D.
Apply reasoning processes and skills to construct logical verifications or counter-examples to test conjectures and to justify and defend algorithms and solutions.
Principles and Standards for School Mathematics
Reasoning and Proof Standard
Select and use various types of reasoning and methods of proof