Chain-of-Thought (CoT) reasoning is a prompt engineering technique that transforms how large language models solve complex problems by explicitly requesting intermediate reasoning steps before generating final answers. Introduced by Google Research in 2022, CoT dramatically improves LLM performance on multi-step reasoning tasks—often by 30-60+ percentage points—by mimicking human problem-solving: breaking down questions, showing work, and building toward solutions iteratively. Unlike direct-answer prompting, CoT makes the model's reasoning process visible and verifiable, enabling better accuracy on mathematical, logical, and symbolic tasks while providing interpretability for debugging and trust. The key insight: explicitly modeling reasoning chains unlocks capabilities that remain dormant in standard prompting.
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This topic spans 13 focused tables and 54 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.
Table 1: Core CoT Prompting Types
| Technique | Example | Description |
|---|---|---|
Q: Roger has 5 balls. He buys 2 more. How many does he have? A: Roger started with 5 balls. 5 + 2 = 7. The answer is 7. Q: A store had 20 apples... | • Provides 2-5 example reasoning chains in the prompt showing step-by-step solutions • the model infers the pattern and applies it to new questions. Most reliable CoT variant for consistent performance. | |
Q: If a train travels 60 mph for 3 hours, how far does it go? A: Let's think step by step. | • Adds the magic phrase "Let's think step by step" to prompts without providing examples• surprisingly effective across models and tasks despite requiring no demonstrations. |