This is interesting. I volunteer at a homework-help clinic for public housing kiddos. They've heard "the answer is right but you got there the wrong way" a lot.

This is interesting. I volunteer at a homework-help clinic for public housing kiddos. They've heard "the answer is right but you got there the wrong way" a lot. It's frustrating to work with the kids, because they say "if I do it that way, the teacher will say I'm wrong." And, I basically don't have a clue about how they're being taught to do this stuff. Any sane person turns 2 x 15 into 2 x 16 - 2 or 10 + 10 + 5 + 5. But this Common Core arithmetic is not quite sane. The intention is to teach reasoning skills, but the reality is that some curriculum-writer's idea of reasoning skills has become codified. Grumble. You'll be missed, Dr. Minsky. So long, and thanks for all your teaching.