Claude on Question 1, Sep 19
Is 91 a prime number? Think step by step and then answer "[Yes]" or "[No]".Step-by-step check
To determine if 91 is prime, I test divisibility by primes up to √91 ≈ 9.54, so I need to check 2, 3, 5, and 7.
Divisible by 2?
91 is odd, so no.
Divisible by 3?
Digit sum: 9 + 1 = 10, which is not divisible by 3, so no.
Divisible by 5?
91 doesn't end in 0 or 5, so no.
Divisible by 7?
91 ÷ 7 = 13 exactly. ✓
So 91 = 7 × 13, meaning it has divisors other than 1 and itself. 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
- 2026-09-19 09:00:12 UTC
- Run
- 20260919T090005Z-86161c
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- Claude Platform on AWS · HTTP 200 · finish stop
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- 444 characters · 353 tokens out incl. hidden reasoning · 5.3 s
Highlighted: the last [Yes]/[No] bracket, which is the scored answer (No).
## Step-by-step check
To determine if 91 is prime, I test divisibility by primes up to √91 ≈ 9.54, so I need to check 2, 3, 5, and 7.
**Divisible by 2?**
91 is odd, so no.
**Divisible by 3?**
Digit sum: 9 + 1 = 10, which is not divisible by 3, so no.
**Divisible by 5?**
91 doesn't end in 0 or 5, so no.
**Divisible by 7?**
91 ÷ 7 = 13 exactly. ✓
So 91 = 7 × 13, meaning it has divisors other than 1 and itself. It is composite.
**[No]**
End of response · 19 lines · 444 characters · sha256 22eb62fcb49bc3c5bbfc790fc7e4c0bb061d2d4e7c200e4f21e4033cfb2a025a