Claude on Question 1, Sep 12
Is 91 a prime number? Think step by step and then answer "[Yes]" or "[No]".Step 1: Check what 91 is.
91 is an odd number greater than 1, so I need to test whether it has any divisors other than 1 and itself.
Step 2: Find the limit for testing divisors.
I only need to test prime divisors up to √91 ≈ 9.54, so I test 2, 3, 5, and 7.
Step 3: Test each prime.
- •2: 91 is odd → not divisible by 2.
- •3: Digit sum = 9 + 1 = 10, which is not divisible by 3 → not divisible by 3.
- •5: 91 doesn't end in 0 or 5 → not divisible by 5.
- •7: 7 × 13 = 91 → divisible by 7!
Step 4: Conclusion.
Since 91 = 7 × 13, it has divisors other than 1 and itself, so it is composite.
[No]
Exact recordShowHideThe model id, the run, the verbatim text with line numbers and its full sha256
- Scored
- answered · correct · format ok
- Received
- 2026-09-12 09:00:29 UTC
- Run
- 20260912T090021Z-c0c86e
- Served by
- Claude Platform on AWS · HTTP 200 · finish stop
- Size
- 633 characters · 320 tokens out incl. hidden reasoning · 4.9 s
Highlighted: the last [Yes]/[No] bracket, which is the scored answer (No).
**Step 1: Check what 91 is.**
91 is an odd number greater than 1, so I need to test whether it has any divisors other than 1 and itself.
**Step 2: Find the limit for testing divisors.**
I only need to test prime divisors up to √91 ≈ 9.54, so I test 2, 3, 5, and 7.
**Step 3: Test each prime.**
- **2:** 91 is odd → not divisible by 2.
- **3:** Digit sum = 9 + 1 = 10, which is not divisible by 3 → not divisible by 3.
- **5:** 91 doesn't end in 0 or 5 → not divisible by 5.
- **7:** 7 × 13 = 91 → **divisible by 7!**
**Step 4: Conclusion.**
Since 91 = 7 × 13, it has divisors other than 1 and itself, so it is composite.
**[No]**
End of response · 16 lines · 633 characters · sha256 fb3231a1c7a5a13e4daf027d6388c56615599cc3230fe992edbd189e9f94175f