Practice question · Select all that apply
Claim: 'every prime number is odd'. Select every value that is a genuine COUNTEREXAMPLE.
Hints
- A counterexample must satisfy the hypothesis but fail the conclusion.
- It must actually be prime, and it must fail to be odd.
Show the answer
- A. 2
Why
Only 2 works: it is prime (satisfying the hypothesis) and even (failing the conclusion). 9 and 15 are odd but not prime, 4 is even but not prime, neither type touches the claim. A counterexample must sit inside the claim's scope.
Practise Direct Proof and Counterexample
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