P2.1.2 - Proof by exhaustion

Proof by exhaustion Proof by exhaustion.; This involves trying all the options.; Suppose x and y are odd integers less than 7.; Prove that their sum is divisible by 2.

Use proof by exhaustion to connect the rule to the data and decision in the question.

This matters because proof by exhaustion determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply proof by exhaustion to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: Proof by exhaustion is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.