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arithfrontier
confirmedPython · CPUModel behavior & reasoningJuly 6, 2026
the question
Where does small-model exact arithmetic break down by digit length, and does CoT push the wall back?
what came out
Multiplication cliffs at 3-4 digits before addition does, the frontier shrinks with model size, and CoT extends it -- the opposite of its effect on retrieval multiple choice. Self-generated exact ground truth.
method & receipts
- Result: confirmed
- Reproducible — one script re-runs the whole thing from scratch.
- Independently reviewed — an adversarial review pass, kept in the repo.
- Machine-readable claims — every reported number, in a checkable file.
- Tested — a correctness/benchmark suite ships alongside the code.
→ read the code and re-run it
github.com/v-code01/arithfrontier