Hacker News new | ask | show | jobs
by sp332 4281 days ago
Common core is not a curriculum. It is not a textbook. It is not a method of subtraction. There are badly-written textbooks both in and outside of Common Core.

Edit: Here we go, Common Core math standards. Grade 2 starts on page 17. http://www.corestandards.org/wp-content/uploads/Math_Standar... Have a look, it's only 4 pages long.

To be specific, this is a third-grade textbook. Students learn subtraction in previous grades, so this is just a quick review before moving on to third-grade topics like multiplication. Notice the problems at the bottom don't require students to use this particular method. If your third-grader can't subtract, they were already behind before you switched to Common Core.

Also, is the method given really that hard to understand? It's probably not my favorite way to subtract, but it's kinda cool.
1 comments
seanflyon 4281 days ago
Just to be clear

"But standardized tests, the SAT, and the ACT are all moving over to Common Core. So our child has to learn this insanity."

which implies that standardized tests test for this particular "counting up" subtraction method. If I understand your statement you are saying that this is not the case.

Right?

link
AnimalMuppet 4281 days ago
It's really hard for a standardized test to measure how you subtracted. (Yes, I am aware that it could be done.) But what it really measures is, can you subtract? Do you get the right answers?

Personally, I don't like this approach, because to do one subtraction, you have to do four additions. That's kind of inefficient, in my view. But as sp332 pointed out, the kids should already know how to subtract numbers by this point. If a kid didn't get it before, this curriculum throws a new method at them, hoping that this one will make sense to them. I'm not sure that I have a problem with the approach (though it wouldn't hurt tweak it so as to not confuse the kids who already know how to subtract).

link
sp332 4281 days ago
I doubt the count-up method was intended to be a new method. I think the new curriculum had it in the second-grade book, and assumed that former second-graders had seen it there. It's not the textbook makers' fault that the school changed between years.
link
sp332 4281 days ago
Common Core standards do not include the counting-up method. So a test that only measures Common-Core compliance would not test for that.
link