Claude on Question 1, Sep 21
Is 91 a prime number? Think step by step and then answer "[Yes]" or "[No]".Step 1: Check what "prime" requires.
A prime number has exactly two distinct positive divisors: 1 and itself.
Step 2: Test divisibility by small primes.
- •2: 91 is odd → not divisible.
- •3: Digit sum = 9 + 1 = 10, not a multiple of 3 → not divisible.
- •5: Doesn't end in 0 or 5 → not divisible.
- •7: 7 × 13 = 91 → divisible!
Step 3: Conclusion.
Since 91 = 7 × 13, it has divisors other than 1 and itself, so it is composite. (Note: √91 ≈ 9.54, so we only needed to check primes up to 9 — and 7 worked.)
[No]
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- Scored
- answered · correct · format ok
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- 2026-09-21 09:00:27 UTC
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- 20260921T090021Z-989a7c
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- Claude Platform on AWS · HTTP 200 · finish stop
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- 547 characters · 280 tokens out incl. hidden reasoning · 4.8 s
Highlighted: the last [Yes]/[No] bracket, which is the scored answer (No).
**Step 1: Check what "prime" requires.**
A prime number has exactly two distinct positive divisors: 1 and itself.
**Step 2: Test divisibility by small primes.**
- **2:** 91 is odd → not divisible.
- **3:** Digit sum = 9 + 1 = 10, not a multiple of 3 → not divisible.
- **5:** Doesn't end in 0 or 5 → not divisible.
- **7:** 7 × 13 = 91 → **divisible!**
**Step 3: Conclusion.**
Since 91 = 7 × 13, it has divisors other than 1 and itself, so it is composite. (Note: √91 ≈ 9.54, so we only needed to check primes up to 9 — and 7 worked.)
**[No]**
End of response · 14 lines · 547 characters · sha256 2d2b6e77a7d3582a0a9f43774aa263c6d6b32c03fbb9a024e77f1bd4ffaf4f60