Building a Thinking Model from a Non-Thinking Model using Chain-of-Thought Prompting

Himanshu negiHimanshu negi
4 min read

Large Language Models (LLMs) like GPT-4, Claude, and Gemini are incredibly capable at generating text, answering questions, and even solving problems. However, not all AI outputs are created equal.

Sometimes, the model jumps straight to the answer without properly reasoning through the problem — which can lead to mistakes. The solution? Chain-of-Thought (CoT) prompting.

With the right prompting, you can turn a non-thinking AI model into one that reasons step-by-step, leading to more accurate and explainable results.


🔹 What is a “Non-Thinking” Model?

When we say a model is “non-thinking,” we don’t mean it literally lacks intelligence — all LLMs are statistical prediction engines. Instead, a “non-thinking” model in this context is:

  • Fast but shallow in reasoning

  • Gives direct answers without showing the process

  • Struggles with multi-step reasoning tasks like math, logic puzzles, or complex planning

For example:
Prompt:

"What’s 37 × 48?"
Non-Thinking Model Output:
"1776"

This might be correct — or it might be a lucky guess. Without reasoning steps, we can’t tell.


🔹 What is Chain-of-Thought Prompting?

Chain-of-Thought (CoT) prompting is a technique where you explicitly ask the model to show its step-by-step reasoning before giving the final answer.

Example:
Prompt:

"Let’s solve this step-by-step. What’s 37 × 48?"

Thinking Model Output:

Step 1: 37 × 40 = 1480
Step 2: 37 × 8 = 296
Step 3: 1480 + 296 = 1776
Final Answer: 1776

This approach helps the model slow down, think logically, and make fewer mistakes.


🔹 Why Chain-of-Thought Works

Chain-of-Thought works because it encourages the model to simulate the same intermediate reasoning process a human would follow. Even though LLMs don’t “think” like humans, prompting them to output intermediate steps activates latent reasoning patterns learned during training.

Benefits include:

  • Higher accuracy for multi-step problems

  • Transparency — you can see how the model got the answer

  • Debuggability — errors become easier to spot and correct


🔹 Turning a Non-Thinking Model into a Thinking Model

Let’s walk through the process.


1️⃣ Identify Reasoning-Heavy Tasks

Chain-of-Thought is most effective for:

  • Math & quantitative reasoning

  • Coding challenges

  • Logical puzzles

  • Planning & strategy tasks

For simple look-up queries, CoT adds unnecessary complexity.


2️⃣ Add Explicit “Think Step-by-Step” Instructions

A minimal way to enable CoT is adding a phrase like:

"Let’s think step-by-step."
"Show your reasoning before the final answer."

Example:
Before (Non-Thinking Prompt):

"If a car travels at 60 km/h for 2.5 hours, how far does it go?"

After (Thinking Prompt):

"If a car travels at 60 km/h for 2.5 hours, let’s solve this step-by-step before giving the final answer."


3️⃣ Use Few-Shot Chain-of-Thought for Stronger Reasoning

Instead of just instructing the model to think step-by-step, show it examples of how you want the reasoning structured.

Example:

Q: What’s 15 × 12?
A: Step 1: 15 × 10 = 150
Step 2: 15 × 2 = 30
Step 3: 150 + 30 = 180
Final Answer: 180

Q: If a train moves at 50 km/h for 4 hours, how far does it travel?
A: Step 1: Speed × Time = Distance
Step 2: 50 × 4 = 200
Final Answer: 200 km

Q: If a car travels at 60 km/h for 2.5 hours, how far does it go?

Now, the model is more likely to follow that pattern reliably.


4️⃣ Use Self-Consistency for Extra Accuracy

Self-Consistency is an advanced CoT approach where the model generates multiple reasoning paths and picks the most common final answer.

This reduces errors from a single flawed reasoning chain.


🔹 Example: Before vs After CoT

Without CoT:
Prompt: “What is 17 × 23?”
Output: “391” (Incorrect — correct answer is 391, so lucky guess here.)

With CoT:
Prompt: “What is 17 × 23? Let’s solve step-by-step.”
Output:

Step 1: 17 × 20 = 340
Step 2: 17 × 3 = 51
Step 3: 340 + 51 = 391
Final Answer: 391 ✅

Even if the final number is the same, CoT makes the process visible and verifiable.


🔹 Best Practices for CoT Prompting

  • Be explicit: “Think step-by-step” is powerful.

  • Show examples: Few-shot CoT improves consistency.

  • Combine with role prompting: “You are a math teacher explaining to a student.”

  • Avoid overuse: For trivial questions, CoT just adds fluff.


🔹 Final Thought

By applying Chain-of-Thought prompting, you can transform a “non-thinking” model into a reasoning companion that explains itself. This technique is especially useful for developers, researchers, and anyone relying on AI for multi-step problem-solving.

In short — don’t just ask for answers; ask for the thinking behind them.

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Himanshu negi
Himanshu negi