So putting it together, the user is asking for a free PDF that teaches English using one formula or method. The task is to create a text explaining this formula in English, probably for someone who wants to learn English without paying or needing special materials.

Also, maybe add a motivational part to encourage the reader to keep going and not get discouraged if progress is slow.

Let me outline steps: start with daily reading, then practice writing, followed by speaking, listening, and expanding vocabulary. Each step can have a brief explanation and tips on how to do it for free.

What's the most effective formula for learning English? It's usually a combination of vocabulary, grammar, and practice. But since the user wants one formula, maybe I can condense it into a daily routine or a specific method.

I should check if there are any common misconceptions about learning English for free. Maybe that it's not effective without paid courses, but the reality is that consistent practice with free resources can be just as good.