If you aren’t sure how to prove what you need prove, work backward. Figure out what is sufficient to prove the conclusion, then prove those things. If you can, some minor editing will give you a complete and valid proof.

**Takeaway Points**

- If you are stuck, try figuring out what is sufficient to prove the conclusion.
- Then try to prove those things.
- By doing this, you are essentially moving your target to something you
*can*do, which will in turn allow you to prove your intended conclusion.