When I was hired as a Geometry teacher I dreaded teaching proofs. I remembered struggling with them when I was in high school. They made me cringe and it seemed as though there was no possible way to teach proofs without receiving that same reaction from my students.
With UNO proof, those feelings changed. I have never seen such excitement during a lesson on proofs. I have used this lesson in multiple schools and the reaction is always the same. They LOVE it! Their understanding of proofs is deeper and we are able to transition from UNO to math quite easily.
Please note: This is only designed to be an introduction to writing two column proofs in order to scaffold the learning of geometric proofs. It is recommended on the first day of proof and reasoning unit.