Sounds like laziness to me, which is of course rampant among teachers.

It does amaze me that googling "common core math" brings up the things it does. Even in a world where we have access to all information, everyone seems to be trying to bullshit everything. I find it very difficult to find the facts on most things.

But when I saw that Khan Academies methods were starting to mirror "The Great Courses" "Secrets of Mental Math"[1] and that it was a part of the common core, I was impressed. Once I started learning things this way, I was better able to handle all math. I used to hate it, dread it. But this kind of thing makes it easy and fun. I'm glad kids are being exposed to it.

[1] http://www.thegreatcourses.com/courses/secrets-of-mental-mat...