Chain of Thought Prompting in Python: Step-by-Step Reasoning Demo

def solve_math_step_by_step(expression: str) -> str:
    """Solves a simple expression, showing each reasoning step."""
    # Step 1: Parse the expression (assume "a + b" or "a - b")
    parts = expression.split()
    a = int(parts[0])
    op = parts[1]
    b = int(parts[2])
    
    steps = []
    steps.append(f"Step 1: Identify the operands → {a} and {b}")
    steps.append(f"Step 2: Identify the operation → {op}")
    
    if op == "+":
        result = a + b
        steps.append(f"Step 3: Compute {a} + {b} = {result}")
    elif op == "-":
        result = a - b
        steps.append(f"Step 3: Compute {a} - {b} = {result}")
    else:
        raise ValueError("Only + and - supported")
    
    steps.append(f"Final Answer: {result}")
    return "\n".join(steps)


if __name__ == "__main__":
    expr = "15 + 7"
    print(f"Expression: {expr}\n")
    print(solve_math_step_by_step(expr))
    print("\n--- Another example ---\n")
    expr2 = "20 - 9"
    print(f"Expression: {expr2}\n")
    print(solve_math_step_by_step(expr2))