Claude Haiku 4.5 vs DeepSeek V3.1 for Math

What Math demands: rigorous stepwise reasoning, accurate tradeoff reasoning with real numbers, faithfulness (no hallucinated steps), consistent long-context handling for multi-step proofs, and often exact structured outputs (LaTeX/JSON) or external-tool use for high-precision computation. Because an external MATH Level 5 score exists in the payload but is empty for both models, we rely on our internal tests. The two task tests here are strategic_analysis and structured_output. Claude Haiku 4.5 scores 5 on strategic_analysis vs DeepSeek V3.1’s 4, and 5 vs 3 on tool_calling (Haiku advantage). DeepSeek V3.1 scores 5 on structured_output vs Haiku’s 4 (DeepSeek advantage). Faithfulness and long_context are tied (both 5), so neither model loses ground there. In short: Haiku shows the better ability to plan and invoke tools for multi-step numeric reasoning; DeepSeek is stronger at strict output formatting.

1. Competitive math solutions (multi-step proofs, strategy-heavy problems): Claude Haiku 4.5 — strategic_analysis 5 vs 4 — provides clearer decomposition and step selection. 2) Problems needing external calculators or sequenced tool use (high-precision arithmetic, multi-query math engine): Claude Haiku 4.5 — tool_calling 5 vs 3 — is preferable. 3) Graded answers, automated pipelines, or judge-friendly JSON/LaTeX outputs where schema compliance matters: DeepSeek V3.1 — structured_output 5 vs 4 — will produce more exact formatted outputs. 4) Generating novel, creative problem sets or non-obvious problem variants: DeepSeek V3.1 — creative_problem_solving 5 vs 4 — is stronger. 5) Long multi-part proofs or exam-length contexts: both tie on long_context (5), so either model handles extended context equally in our tests. Also factor cost: Claude Haiku 4.5 is pricier (input 1 / output 5 per mtok) vs DeepSeek V3.1 (input 0.15 / output 0.75 per mtok); our priceRatio indicates Haiku runs ~6.67x more expensive by the provided cost metrics.

For Math, choose Claude Haiku 4.5 if you need top-tier strategic reasoning and reliable tool/calc orchestration (strategic_analysis 5, tool_calling 5). Choose DeepSeek V3.1 if you prioritize exact, schema-compliant outputs or creative problem generation (structured_output 5, creative_problem_solving 5) and want lower per-token cost.