# Best LLM for Logic & Problem Solving > Updated Oct 20, 2026 ยท evidence through Oct 20, 2026. Synthesized from cited community evidence and open benchmarks, not vendor marketing. Canonical page: https://modelmatchbook.com/best/reasoning-general Gemini 4 Argon ranks first for Logic & Problem Solving as of October 20, 2026. It ranks #1 of 148 on LMArena's maths category (Elo 1536), based on blind human preference votes for maths prompts. Gemini 3.8 Flash is the next-ranked alternative. It scores 81.41% on LiveBench Instruction Following (#1 of 59), including paraphrasing, simplifying, story generation, and summarization. [1,2] ## 1. Gemini 4 Argon https://modelmatchbook.com/models/google/gemini-4-argon-20261013 Gemini 4 Argon ranks #1 of 148 on LMArena's maths category (Elo 1536), based on blind human preference votes for maths prompts. **Best when:** Its strongest result for this task is on LMArena Math, which measures math answers people prefer in blind comparison. [1] ## 2. Gemini 3.8 Flash https://modelmatchbook.com/models/google/gemini-3.8-flash-20260902 Gemini 3.8 Flash scores 81.41% on LiveBench Instruction Following (#1 of 59), including paraphrasing, simplifying, story generation, and summarization. **Best when:** Its strongest result for this task is on LiveBench Instruction Following, which measures following detailed instructions exactly. [2] ## 3. Claude Fable 5.1 https://modelmatchbook.com/models/anthropic/claude-fable-5.1-20260831 Claude Fable 5.1 ranks #3 of 148 on LMArena's maths category (Elo 1528), based on blind human preference votes for maths prompts. **Best when:** Its strongest result for this task is on LMArena Math, which measures math answers people prefer in blind comparison. [3] ## 4. GPT-6 Astra https://modelmatchbook.com/models/openai/gpt-6-astra-20260903 GPT-6 Astra tops LiveBench Reasoning at 92.65% and ranks #2 on GPQA Diamond, though it underperforms on human preference metrics for maths and instruction-following. **Best when:** Choose for objective reasoning benchmarks where it scores 92.65% on LiveBench Reasoning, #1 of 59. [4] **More tips:** - Use for graduate science questions where it scored 95.8% on GPQA Diamond, #2 of 113. [5] **Watch out for:** - Expect weaker human preference performance on maths tasks, ranking #40 of 148 with Elo 1465. [6] - Anticipate lower instruction-following appeal, ranking #35 of 152 with Elo 1455. [7] ## 5. GPT-6.1 Sol https://modelmatchbook.com/models/openai/gpt-6.1-sol-20260929 GPT-6.1 Sol scores 92.63% on LiveBench Reasoning (#2 of 59), an objective, ground-truth-scored evaluation refreshed with new questions. **Best when:** Its strongest result for this task is on LiveBench Reasoning, which measures multi-step reasoning. [8] ## 6. Gemini 3.7 Flash https://modelmatchbook.com/models/google/gemini-3.7-flash-20260813 Gemini 3.7 Flash scores 79.93% on LiveBench Instruction Following (#2 of 59), including paraphrasing, simplifying, story generation, and summarization. **Best when:** Its strongest result for this task is on LiveBench Instruction Following, which measures following detailed instructions exactly. [9] ## 7. Claude Opus 5.5 https://modelmatchbook.com/models/anthropic/claude-opus-5.5-20260921 Claude Opus 5.5 ranks #1 of 152 on LMArena's instruction-following category (Elo 1536), based on blind human preference votes. **Best when:** Its strongest result for this task is on LMArena Instruction Following, which measures following instructions as people judge them. [10] ## 8. Muse Spark 1.3 https://modelmatchbook.com/models/meta/muse-spark-1.3-20260902 Muse Spark 1.3 scores 78% on LiveBench Instruction Following (#4 of 59), including paraphrasing, simplifying, story generation, and summarization. **Best when:** Its strongest result for this task is on LiveBench Instruction Following, which measures following detailed instructions exactly. [11] ## FAQ **What is the best model for Logic & Problem Solving?** Gemini 4 Argon ranks first as of October 20, 2026. Gemini 4 Argon ranks #1 of 148 on LMArena's maths category (Elo 1536), based on blind human preference votes for maths prompts. [1] **What is the best alternative to Gemini 4 Argon?** Gemini 3.8 Flash ranks second. Gemini 3.8 Flash scores 81.41% on LiveBench Instruction Following (#1 of 59), including paraphrasing, simplifying, story generation, and summarization. [2] ## Sources 1. "Within the 148 catalog models matched to this evaluation: Ranks #1 of 148 on LMArena's maths category (Elo 1536), based on blind human preference votes for maths prompts." (LMArena maths category, https://lmarena.ai/leaderboard) 2. "Within the 59 catalog models matched to this evaluation: Scores 81.41% on LiveBench Instruction Following (#1 of 59), including paraphrasing, simplifying, story generation, and summarization." (LiveBench Instruction Following, https://livebench.ai/) 3. "Within the 148 catalog models matched to this evaluation: Ranks #3 of 148 on LMArena's maths category (Elo 1528), based on blind human preference votes for maths prompts." (LMArena maths category, https://lmarena.ai/leaderboard) 4. "Within the 59 catalog models matched to this evaluation: Scores 92.65% on LiveBench Reasoning (#1 of 59), an objective, ground-truth-scored evaluation refreshed with new questions." (LiveBench Reasoning, https://livebench.ai/) 5. "Within the 113 catalog models matched to this evaluation: Scores 95.8% on GPQA Diamond in Epoch AI's independent run (#2 of 113), graduate-level science questions." (GPQA Diamond (Epoch AI), https://epoch.ai/benchmarks) 6. "Within the 148 catalog models matched to this evaluation: Ranks #40 of 148 on LMArena's maths category (Elo 1465), based on blind human preference votes for maths prompts." (LMArena maths category, https://lmarena.ai/leaderboard) 7. "Within the 152 catalog models matched to this evaluation: Ranks #35 of 152 on LMArena's instruction-following category (Elo 1455), based on blind human preference votes." (LMArena instruction-following category, https://lmarena.ai/leaderboard) 8. "Within the 59 catalog models matched to this evaluation: Scores 92.63% on LiveBench Reasoning (#2 of 59), an objective, ground-truth-scored evaluation refreshed with new questions." (LiveBench Reasoning, https://livebench.ai/) 9. "Within the 59 catalog models matched to this evaluation: Scores 79.93% on LiveBench Instruction Following (#2 of 59), including paraphrasing, simplifying, story generation, and summarization." (LiveBench Instruction Following, https://livebench.ai/) 10. "Within the 152 catalog models matched to this evaluation: Ranks #1 of 152 on LMArena's instruction-following category (Elo 1536), based on blind human preference votes." (LMArena instruction-following category, https://lmarena.ai/leaderboard) 11. "Within the 59 catalog models matched to this evaluation: Scores 78% on LiveBench Instruction Following (#4 of 59), including paraphrasing, simplifying, story generation, and summarization." (LiveBench Instruction Following, https://livebench.ai/)