These changes came to our elementary school when my youngest was in 4th grade. My H and I were discussing this thread and how we remember struggling to help S with his homework. He brought home problems of simple addition like 42+89 and we would explain about carrying, etc, and work it out with him. He would get frustrated with us and say, “Yes, I know how to do it that way and I know the answer, but we have to do it this way or it gets marked wrong”—and he starts talking about adding by 10s and arrays and writing paragraphs to explain each step, etc.
We didn’t have a clue. It boggled my mind that he could have the answer correct but because he used the “wrong” method, it was marked incorrect or 1/2 credit. Why can’t kids use whatever method comes easiest? Some kids can do it in their heads–so what? He would often end up working backwards from the answer and plugging in the common core stuff instead of using these new ways to GET the answer in the first place.
I was glad when he got to algebra, because as far as I can tell, it is the same as when I learned it back in the day and it is much easier for us to help him now.