This post is not necessarily about education or Common Core but I think it is something that should be brought to come people's attention.
No one can ever be equal. Whether or not you believe in a god or fate, we were all born to do and be something, something unique to us. No two people are meant to be equal, not academically, skillfully, politically, or socially. And why would you want to be? If we were all equal there would be no new ideas, and we would never progress as a species.
If every single person had all the opportunities available handed to them everyone would be of an equal status and couldn't learn from each other. The fact that some people find it harder to learn math doesn't mean we should dumb it down to accommodate everyone, it means we help them the best we can in math and then we help them discover something they are great at. Because everyone is great at something. And thankfully there are so many things to be good at that no one is exactly the same.
We cannot try to take 7 billion people who were all born in different places, into different situations, with naturally different abilities and try to make them as common as possible. Why would we ever want to do that? Why would we want to make everything as easy as possible for everyone so that no one gets left behind? What would we gain? This is life, some people are going to get left behind, it is inevitable, it is a fact of nature. But they won't be stuck there, not if they don't want to. They will find something they are great at and excel. And that is what we should focus on. Making sure every child finds something they are great at and embraces it to their full ability and develops a passion for it. We should not make everything easier because we are afraid of kids thinking they are dumb. If you try you can never be dumb. School does not measure your success, you do. As the leaders of our society it is up to us to make sure every child knows that.
So find what you are great at and love it and make a life out of it. Don't try to keep up with everyone else. We should not adopt a system that has "Common" in the name, because by nature we are not common and we are never going to be. We are all magnificently different and we all excel at something. We are equal in value but not in ability.