Claude on Question 2, Sep 12
Is 9973 a prime number? Think step by step and then answer "[Yes]" or "[No]".Checking 9973
Since √9973 ≈ 99.9, I only need to test prime divisors up to 99.
- •2: 9973 is odd → no
- •3: digit sum = 9+9+7+3 = 28, not a multiple of 3 → no
- •5: doesn't end in 0 or 5 → no
- •7: 7 × 1424 = 9968, remainder 5 → no
- •11: alternating sum 9−9+7−3 = 4 → no
- •13: 13 × 767 = 9971, remainder 2 → no
- •17: 17 × 586 = 9962, remainder 11 → no
- •19: 19 × 524 = 9956, remainder 17 → no
- •23: 23 × 433 = 9959, remainder 14 → no
- •29: 29 × 343 = 9947, remainder 26 → no
- •31: 31 × 321 = 9951, remainder 22 → no
- •37: 37 × 269 = 9953, remainder 20 → no
- •41: 41 × 243 = 9963, remainder 10 → no
- •43: 43 × 231 = 9933, remainder 40 → no
- •47: 47 × 212 = 9964, remainder 9 → no
- •53: 53 × 188 = 9964, remainder 9 → no
- •59: 59 × 169 = 9971, remainder 2 → no
- •61: 61 × 163 = 9943, remainder 30 → no
- •67: 67 × 148 = 9916, remainder 57 → no
- •71: 71 × 140 = 9940, remainder 33 → no
- •73: 73 × 136 = 9928, remainder 45 → no
- •79: 79 × 126 = 9954, remainder 19 → no
- •83: 83 × 120 = 9960, remainder 13 → no
- •89: 89 × 112 = 9968, remainder 5 → no
- •97: 97 × 102 = 9894, remainder 79 → no
No prime ≤ 99 divides 9973, so it is prime (in fact, it's the largest four-digit prime).
[Yes]
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 09:00:55 UTC
- Run
- 20260912T090021Z-c0c86e
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- Claude Platform on AWS · HTTP 200 · finish stop
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- 1,287 characters · 1,381 tokens out incl. hidden reasoning · 12.4 s
Highlighted: the last [Yes]/[No] bracket, which is the scored answer (Yes).
## Checking 9973
Since √9973 ≈ 99.9, I only need to test prime divisors up to 99.
- **2:** 9973 is odd → no
- **3:** digit sum = 9+9+7+3 = 28, not a multiple of 3 → no
- **5:** doesn't end in 0 or 5 → no
- **7:** 7 × 1424 = 9968, remainder 5 → no
- **11:** alternating sum 9−9+7−3 = 4 → no
- **13:** 13 × 767 = 9971, remainder 2 → no
- **17:** 17 × 586 = 9962, remainder 11 → no
- **19:** 19 × 524 = 9956, remainder 17 → no
- **23:** 23 × 433 = 9959, remainder 14 → no
- **29:** 29 × 343 = 9947, remainder 26 → no
- **31:** 31 × 321 = 9951, remainder 22 → no
- **37:** 37 × 269 = 9953, remainder 20 → no
- **41:** 41 × 243 = 9963, remainder 10 → no
- **43:** 43 × 231 = 9933, remainder 40 → no
- **47:** 47 × 212 = 9964, remainder 9 → no
- **53:** 53 × 188 = 9964, remainder 9 → no
- **59:** 59 × 169 = 9971, remainder 2 → no
- **61:** 61 × 163 = 9943, remainder 30 → no
- **67:** 67 × 148 = 9916, remainder 57 → no
- **71:** 71 × 140 = 9940, remainder 33 → no
- **73:** 73 × 136 = 9928, remainder 45 → no
- **79:** 79 × 126 = 9954, remainder 19 → no
- **83:** 83 × 120 = 9960, remainder 13 → no
- **89:** 89 × 112 = 9968, remainder 5 → no
- **97:** 97 × 102 = 9894, remainder 79 → no
No prime ≤ 99 divides 9973, so it is prime (in fact, it's the largest four-digit prime).
**[Yes]**
End of response · 33 lines · 1,287 characters · sha256 26ee7f804c21b3736ea382fa9fa0e6ba6ae777cf42ff835b8e325fca4e678df4