I do that when I’m computing large numbers. It does make it easier at times to do that, so it’s not totally worthless.
However, it’s probably too early to introduce that sort of mathematical principle. You can’t teach algebraic principles to,kids who are still learning basic math.
You know that, and I know that, but all the "education experts" don't know that.
“You can’t teach algebraic principles to,kids who are still learning basic math.”
But maybe you can teach them that there is more than one way to solve a problem....heck, it worked for Gauss and summations :-)
Remember that what we are looking at here is just a very easy example being used to illustrate a larger concept. So, of course it looks a little silly. But I wish I had been taught more along these lines rather than just memorize, memorize and memorize.
As for what the appropriate age is for this sort of thing...I admit that I have no idea :-)
I also do that (in my head) but I do NOT call it: “using number bonds to help skip-count by seven by making tens or adding to the ones”.
That phrase is nonsense: both mathematically and linguistically.
I wonder what it is that libs have against rote memorization.
Every child should as a basis for learning math, have the addition and multiplication tables memorized for all the single digit numbers.
Not drilling this memorization into them early is simply handicapping them.
Now, the “skip counting” IS useful, to a certain point.
And, I’ve used it when my kids get rowdy in the back seat and need something to occupy their minds besides pestering each other.
“Skip count to 200 by 17’s - GO!”
I agree totally but I suspect that the real explanation is that math is not as easy to corrupt as many other subjects. In history, for example, you just hide the truth and teach lies disguised as history. In math the truth is demonstrable so you must muddy the water by teaching methods for which the student is not ready and apparently some may never be ready. Modern “educators” have been able to produce university graduates who would stand zero chance of passing an eighth grade history test from 1950 even though they may have MAJORED in history. Now they take on the daunting task of producing university graduates who are uncertain about adding single digit numbers. I know it is like trying to herd cats but give them time, they will find a way. Give them time and they will make the characters in “IDIOCRACY” look like a world of geniuses.
Isaac Asimov had a book in the 60s called “Quick and Easy Math”. Popular Science magazine included excerpts in the December 1964 issue:
http://books.google.com/books?id=WCYDAAAAMBAJ&lpg=PA77&pg=PA77#v=onepage...
The technique shown on this test is nothing new. What IS new is shrouding a simple concept in incomprehensible gobbledygook so no sane person could understand it. Thanks, Education Establishment.
I put the tips in the PopSci article to great use immediately after I read them (8th grade) and still use them every day. Teaching these brilliant shortcuts to 9 year olds is just nuts because they haven’t mastered the basics.
I do that in my head for large numbers too I was helping my granddaughter one time at math when she was about 9 or 10 and she said how did you know the answer so quick? When I explained to her something like...I just added 10s and then subtracted 2 twice because...... she looked at me like I was nuts. Blank stare. Lol
Me too. And I'm known for being quick with addition. However, I picked it up on my own.
That’s an application of the Associative Property of Addition. It’s useful, as you say, for adding large numbers. Multiplication also has an Associative Property, and can be handled similarly. Again, it is useful for managing large numbers.
Seven is not a large number.
Memorizing that 7+7=14 is useful.
No, but you can so frustrate them trying to 'teach' them this intellectual swill to the point they no longer even TRY or WANT to learn....they just do what they're told.
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My twins graduated a few years back, and when they were in elementary school they were given some asinine homework with addition and subtraction by grouping into tens. I called the teacher at home to discover it was a backasswards way of what we called 'borrowing'- (but then, we spent a solid year just adding and subtracting different amounts with various-sized groups of numbers)
It was shortly afterward I discovered the lessons hopped back and forth in mathematical principals to the point they made little sense.
Kids in todays *educational* system no longer suffer through the angst of having to recite multiplication tables until they puke like their parents did.
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!”