Ok, let me start by saying I'm in my 37th year of teaching and I have been through 3 rounds of curriculum changes. I have taught both honors, Regents, and non-Regents Geometry throughout all of my career as well as AP Calculus. I also consider myself to be quite open-minded when it comes to curriculum changes. Having said this I'm at a loss of words to describe the "proofs" presented in Geometry Module 1. The lack of rigor in notation drives me nuts, and I know, the context of the problem should help students differentiate between AB=CD meaning congruence vs equality. But now we have reasons like "prop of isos triangle" and "<'S on a line", not to mention the fact that the final statement in the proof needs no reason. For example, take a look at proof#3 on page 191...what happened the Substitution Post. and the Subtraction Post.(not to mention the fact we would have used the Linear Pair Theorem and the Congruent Supplements Theorem in the first place)? What worries me is that if we don't adopt the "new language" and adopt their system of proof our students will be clueless on multiple choice questions. There are several thing about cc I like, even defining congruence via rigid motions but having to unlearn a course I've taught for so long with so much emphasis on rigor is going to be very difficult. We've previewed many NYS texts supposedly aligned to the CC and they look nothing like the modules. What do the rest of you think?