I always found setting up proportions fun-easy and was initially alarmed about CCSS switching us to direct variation. As I studied the progressions, it made sense; but until last week I was skeptical about whether the students could do it. In the past, my k was upside-down half the time with DV. We have been meeting with our Freshmen science teachers in recent weeks, and my concerns evaporated when they stresed the need for units. When units are included in a DV equation, getting k right is easy. It occurred to me that our science/math curriculums have been working against each other for a very long time: DV vs. setting up proportions. My colleagues have been through many curriculum revolutions in their careers, and I understand when they say CCSS is just one more to blow away shortly. But I believe if we emphasize the efficiency that would result with this single change, we would have a very strong sell among skeptics. I think our science teachers may be our best ally as we try to move forward.