I seriously don’t see a problem with this.
I’m an engineer, and I take math shortcuts like this all the time.
For instance, what’s 29 + 39?
(Borrow one from 29 to give to the 39)
It’s now 28 + 40, or 68.
What’s 13 x 13?
Its 13 x 10 + 13 x 3.
So, 130 + 39, or 169.
This is why people like me can split up a check in my head while the rest of you are hunting for a calculator.
If Common Core is bad, then fine it’s bad. But it’s not bad because of math problems like this example. It seems as though “Common Core” has become the right wing’s “Squirrel!”
It’s ok to take shortcuts, when you understand the problem. That’s why you are able to take the shortcuts and get the proper answer.
However, Common Core is trying to teach those short cuts before the kids have mastered the material. It’s the same reason why kids literacy rates are lower from a generation ago, they were taught to memorize words with no understanding of the phonetics behind those words.
It's also not bad simply because it is universally required. What makes it bad is that the freedom to improve it has been eliminated in favor of allowing the GOVERNMENT to control its content.
Tolerance for getting the wrong answer if the proper procedure is used misses the point completely; that is, to get the right answer.