You’re confusing engineering with maths. You engineer your prompting to maximize the chance the LLM does what you need - in your example, the true answer - to get you closer to solving your problem. It doesn’t matter what the LLM does internally as long as the problem is being solved correctly.
(As an engineer it’s part of your job to know if the problem is being solved correctly.)
(As an engineer it’s part of your job to know if the problem is being solved correctly.)