Claude on Question 1, Sep 30

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 it could potentially be prime. I need to test divisibility by primes up to √91 ≈ 9.54, so I check 2, 3, 5, and 7.

Step 2: Test divisibility by 2.
91 is odd, so it's not divisible by 2.

Step 3: Test divisibility by 3.
Digit sum: 9 + 1 = 10, which is not divisible by 3. So 91 is not divisible by 3.

Step 4: Test divisibility by 5.
91 doesn't end in 0 or 5, so it's not divisible by 5.

Step 5: Test divisibility by 7.
7 × 13 = 91. ✓ So 91 is divisible by 7.

Conclusion: Since 91 = 7 × 13, it has divisors other than 1 and itself, meaning it is composite.

[No]

sha256 30e64fbd046d… · 38 tokens in · 337 out · 4.7 s · via Claude Platform on AWS · stopped on its own

Sep 30, the whole day Question 1, every day

Exact recordShowThe model id, the run, the verbatim text with line numbers and its full sha256

Model: anthropic/claude-opus-5
pinned anthropic/claude-opus-5-20260723; alias resolved to anthropic/claude-opus-5-20260723 at 2026-09-30 09:00:07 UTC (matches the pin)
Date: 2026-09-30 · run 20260930T090007Z-45ce12 · scorer v1
Scored: answered · correct · format ok
sha256: 30e64fbd046d33c9a2bc9aa6924967602cd3038cb364fecf249417994cc5cd2b
Permalink: https://modeldrift.watch/r/2026-09-30/D1/anthropic/claude-opus-5/

Scored: answered · correct · format ok
Received: 2026-09-30 09:00:13 UTC
Run: 20260930T090007Z-45ce12
Served by: Claude Platform on AWS · HTTP 200 · finish stop
Size: 659 characters · 337 tokens out incl. hidden reasoning · 4.7 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 it could potentially be prime. I need to test divisibility by primes up to √91 ≈ 9.54, so I check 2, 3, 5, and 7.
**Step 2: Test divisibility by 2.**
91 is odd, so it's not divisible by 2.
**Step 3: Test divisibility by 3.**
Digit sum: 9 + 1 = 10, which is not divisible by 3. So 91 is not divisible by 3.
**Step 4: Test divisibility by 5.**
91 doesn't end in 0 or 5, so it's not divisible by 5.
**Step 5: Test divisibility by 7.**
7 × 13 = 91. ✓ So 91 *is* divisible by 7.
**Conclusion:** Since 91 = 7 × 13, it has divisors other than 1 and itself, meaning it is composite.
**[No]**

End of response · 18 lines · 659 characters · sha256 30e64fbd046d33c9a2bc9aa6924967602cd3038cb364fecf249417994cc5cd2b