City-Data Forum Common core math... A second grade practice question that the student couldn't answer so his dad helped out. His answer (solution, school)
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03-21-2014, 06:58 AM
 Location: Plymouth Meeting, PA. 4,009 posts, read 2,054,411 times Reputation: 1918

https://scontent-b.xx.fbcdn.net/hpho...67189095_n.jpg

03-21-2014, 07:14 AM
 6,867 posts, read 2,517,651 times Reputation: 3730
What's funny about Common Core math is that for things like subtraction and division, they teach endless approximations instead of the standard arithmetic methods. This may sound like it is easier than learning a specific method, but here's the thing...endless approximation is essentially Calculus. In Calc I, you first learn about derivatives by endless approximation of tangent lines towards a specific point, and in Calc II, you first learn about integration as endless approximation of rectangles under a curve.

So common core, this thing that is supposed to make math easier, uses Calculus techniques to teach arithmetic? Uhm...OK?

537 - 426 is much easier to solve by (7-6)+(30-20)+(500-400). Successive single digit subtraction, where the hardest part is the "borrowing" concept we all learned the 2nd week of 2nd grade. Endless approximation? Not sure why we need to informally introduce lim x; x--> thinking to elementary school kids to teach them arithmetic, but then again, most new age nonsense escapes me.

03-21-2014, 07:31 AM
 Location: Londonderry, NH 41,492 posts, read 51,348,324 times Reputation: 24612
Volo---- I thought I invented that technique. Oh well. I use successive approximations to take square roots in my head.

Why don't the just teach arithmetic including the 15 x 15 times table?

03-21-2014, 07:32 AM
 Location: Great State of Texas 86,093 posts, read 72,460,873 times Reputation: 27565
The tried and true simple methods of traditional math are no longer seen as valid.
Why I have no clue.

And CC will start to show it's results when the next PISA test is administered in 3 years.
We fell to #36 in 2012 for Math.

03-21-2014, 07:34 AM
 Location: Great State of Texas 86,093 posts, read 72,460,873 times Reputation: 27565
Quote:
 Originally Posted by GregW Volo---- I thought I invented that technique. Oh well. I use successive approximations to take square roots in my head. Why don't the just teach arithmetic including the 15 x 15 times table?
And that's where it's more appropriate to use.
But to use on simple straightforward subtraction and addition is nuts.

As to your question about why .... rote learning is considered bad.
They want "critical thinking" and "deep understanding" and "mastery" of the subject.

Tell that to a 6 or 7 year old and watch for that "deer in the headlights" look

03-21-2014, 07:37 AM
 6,867 posts, read 2,517,651 times Reputation: 3730
Quote:
 Originally Posted by GregW Why don't the just teach arithmetic including the 15 x 15 times table?
Apparently, rote memorizing multiplication tables up to 15, adding/subtracting single digits from right to left, and putting them all together to understand long division...so that precise, exact answers can be quickly and easily computed is the same as cruel and unusual punishment, so estimation, approximation and feeling good about any answer, right or wrong, is preferable.

03-21-2014, 07:40 AM
 6,867 posts, read 2,517,651 times Reputation: 3730
Quote:
 Originally Posted by HappyTexan And CC will start to show it's results when the next PISA test is administered in 3 years. We fell to #36 in 2012 for Math.
Yep. We'll be outside the top 50 and envying 3rd world nations for their mathematical prowess by 2020, because nothing destroys nearly as well as a bunch of idiots with good intentions.

03-21-2014, 07:40 AM
 Location: In the realm of possiblities 2,713 posts, read 2,279,635 times Reputation: 3239
We have a neighbor whose young son was telling us all about this type of "math". He told us the teacher requires the class to explain why equations produce the answer that they do. He seems to grasp the basics behind the concept, but the whole thing is as foreign as Fermat's theorem to us, and his parents . I am like this parent that wrote the letter. The answer is the answer, because it is. Simple as that. Life can be difficult enough without adding to it.

03-21-2014, 07:40 AM
 Location: Plymouth Meeting, PA. 4,009 posts, read 2,054,411 times Reputation: 1918
yeah I had Calc 1 and Calc2 and hated approximations.
I always argued what this guy said about getting the solution in timely manner.
If you need to get an answer quickly, I don't think you have time to do graphs, approximations or whatever. It's just more making our kids slower and behind the rest of the world.

Quote:
 Originally Posted by Volobjectitarian What's funny about Common Core math is that for things like subtraction and division, they teach endless approximations instead of the standard arithmetic methods. This may sound like it is easier than learning a specific method, but here's the thing...endless approximation is essentially Calculus. In Calc I, you first learn about derivatives by endless approximation of tangent lines towards a specific point, and in Calc II, you first learn about integration as endless approximation of rectangles under a curve. So common core, this thing that is supposed to make math easier, uses Calculus techniques to teach arithmetic? Uhm...OK? 537 - 426 is much easier to solve by (7-6)+(30-20)+(500-400). Successive single digit subtraction, where the hardest part is the "borrowing" concept we all learned the 2nd week of 2nd grade. Endless approximation? Not sure why we need to informally introduce lim x; x--> thinking to elementary school kids to teach them arithmetic, but then again, most new age nonsense escapes me.

03-21-2014, 07:42 AM
 16,272 posts, read 9,105,195 times Reputation: 6546
i havent found much about common core that i like...

I can say as a grown up, I sure am glad for excel spreadsheets and =sum(567-382)

LOL!
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