A lot of the problem people associated the Common Core math is the problem of the reform math. Unlike Val, I am quite okay with decomposing numbers and number bonds. That is how I do mental math and it feels natural to me. The reform math comes in when the kids are required to draw everything, explain everything and that is really annoying. The bad text books and bad test questions exacerbate the issue.

I always find it interesting that American teachers found Singapore Math hard to teach. I happen to love it.