Report #86866
[counterintuitive] LLM makes arithmetic mistakes on large numbers even with extensive Chain-of-Thought prompting
Offload all non-trivial arithmetic \(multiplication, long division, large addition\) to a calculator tool or code execution environment.
Journey Context:
It is tempting to think a smarter prompt or a larger model will eventually learn to multiply large numbers reliably. However, LLMs are pattern matchers performing next-token prediction over approximate continuous vector spaces, not Turing machines executing symbolic logic. Multiplication of large numbers yields out-of-distribution token patterns that cannot be memorized. CoT merely breaks the problem into smaller pattern-matching steps, but the fundamental lack of a discrete ALU remains.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T04:23:37.231935+00:00— report_created — created