Is it just me or did the author screw up during their lattice multiplcation process?

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Zstream

Diamond Member
Oct 24, 2005
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I'm going to disagree with our (old) way being so much better. Americans learn math via a lot of more or less unrelated algorithms that they have to memorize. The average high school student doesn't "understand" math, they just know "how" to do it. Memorize the procedure for this, memorize the procedure for that.

Perhaps it'll be simplest to illustrate this with 2x2. Let's say 36 times 47. Let's do it "backwards" from the American (we think we're superior, hence we're the only country in the world to not use the metric system, though our system has been defined in terms of SI units since the 1890s) method. The American method would have you multiply the 6 and 7 first.

Let's multiply the 30 and 40 first. 1200. Then, more or less grouped together (which is done automatically with the lattice system), 6 40s (240 more, running total 1440 for those mentally multiplying) and 7 30s (another 210, 1650 for those keeping tally in their head) and finally the 6 times 7 for 42 more (1692). So, for many of those students writing it out, the work looks like: 1200 + 240 + 210 + 42. Cue in parents, "my way is a little better because it's just slightly quicker! Plus I understand it." No, the average parent doesn't *understand* it; they just know *how* to do it and can describe that process better.

Now, fast forward 4 years. Algebra time. Instead of 36 and 47, it's (x+6) and (x+7). Holy shit, it's the exact same thing to the common core kids. Nothing new. (Does that help explain why at about 4th grade, US kids are keeping pace with those in other kids, but around Algebra time, we look like idiots?) To Americans who learned the old "superior" method, now the idiotic kids in America have to learn FOIL stands for first, outer, inner, last. And, like I said, math becomes a pile of disjunct procedures that American kids have to memorize - no understanding happens for the vast majority of them.

Unfortunately, and this is a huge failure, there has been virtually zero training for teachers who have had CC thrust upon them. This is especially true of elementary teachers who (not all of them) are generally very poor at math. They don't *understand* the new procedures or why these new methods are being taught instead of the old methods. If teachers don't understand, how the hell are they going to teach the students so that the students understand??

Well, what do you my method? I do 345 x 5 = 1725 (300 * 5 + 40 * 5 + 5 * 5) = 1725 * 3?
 

alkemyst

No Lifer
Feb 13, 2001
83,769
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The problem with common core is so much of the questions require you use the method they are asking for to solve the problem. I could agree if you could use any method, show your work and if you got a correct answer...then you were golden.

So now the student has to remind 'methods' on top of the problems and the teachers seem to use a different name for the methods then the test sheets do.
 

ch33zw1z

Lifer
Nov 4, 2004
38,130
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After learning how it works, I found it pretty straight forward. It was easier to check the work too, especially when you start doing bigger numbers.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
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www.slatebrookfarm.com
I've seen a lot of common core crap that looks like the person making the question didn't have a clue about what was being taught or why. E.g., if you have 437 minus 298, you could subtract 300, then add 2. And, you can make sense of that method. You could talk about how 300 minus 2 is 298, and how if you 437 - (300 - 2), you can discuss all those properties such as distributive, commutative, and associative. Though, you don't necessarily have to give them the names of those properties. Though, I often scratch my head wondering my one vocabulary term is considered too difficult for little kids (commutative) when they learn that 5+7 gives the same answer as 7+5; and that's too difficult of a term to introduce until, say, high school.

But, some of the problems and examples to develop this idea are so convoluted... it doesn't make sense to do it the way they have it in the examples. i.e. "subtract 270, then add in 40, then..."
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
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After learning how it works, I found it pretty straight forward. It was easier to check the work too, especially when you start doing bigger numbers.

Lattice and Matrix methods are very easy.

However; this conversation is more about the rest of common core and how there is a disjunct between the teachers, books, tests, and students and esp. the parents.
 

ch33zw1z

Lifer
Nov 4, 2004
38,130
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Lattice and Matrix methods are very easy.

However; this conversation is more about the rest of common core and how there is a disjunct between the teachers, books, tests, and students and esp. the parents.

What coversation? Where did I discuss this with you?

My comments are about finding lattice multiplication today, 25 years after I started multiplication at the age of 8, and comparing it to the way I was taught.
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
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What coversation? Where did I discuss this with you?

My comments are about finding lattice multiplication today, 25 years after I started multiplication at the age of 8, and comparing it to the way I was taught.

The conversation of this thread?
 

ch33zw1z

Lifer
Nov 4, 2004
38,130
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The conversation of this thread?

I haven't read all the posts. Never quoted or joined in anything. I've responded to the OP.

Were you just looking for a pat on the back? Lattice and matrix math very easy for you bro?
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
I haven't read all the posts. Never quoted or joined in anything. I've responded to the OP.

Were you just looking for a pat on the back? Lattice and matrix math very easy for you bro?

Wow...I was just commenting.

Yes, they are easy for me...you have to do the math to get to that level. I have had Matrix Theory and other advanced math though.

Nice attack, bro.
 

ch33zw1z

Lifer
Nov 4, 2004
38,130
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Wow...I was just commenting.

Yes, they are easy for me...you have to do the math to get to that level. I have had Matrix Theory and other advanced math though.

Nice attack, bro.

Lattice and Matrix methods are very easy.

However; this conversation is more about the rest of common core and how there is a disjunct between the teachers, books, tests, and students and esp. the parents.

Commenting on what exactly? I wasn't involved in whatever discussion you were having, yet you felt the need to present my post as if I was.

You already did it, great. Have a cookie.

Just commenting, puh-leeze. Next time you feel like "just commenting", take a deep breath and think about why you feel that way.
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Commenting on what exactly? I wasn't involved in whatever discussion you were having, yet you felt the need to present my post as if I was.

You already did it, great. Have a cookie.

Just commenting, puh-leeze. Next time you feel like "just commenting", take a deep breath and think about why you feel that way.

I was responding to the topic, her209 created.

Are you trying to do something that will get me banned?

Yeah, you are.

digital-account-management-clever-girl.jpg
 

Ruptga

Lifer
Aug 3, 2006
10,246
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I was responding to the topic, her209 created.

Are you trying to do something that will get me banned?

Yeah, you are.

digital-account-management-clever-girl.jpg

So are you going to take us up on that or are you chicken, chicken?

From the little I've seen, I like the common core math. It looks a lot like what I do when I do mental math.
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
So are you going to take us up on that or are you chicken, chicken?

From the little I've seen, I like the common core math. It looks a lot like what I do when I do mental math.

You seem to want a fight. I reported this. I am not chicken, this is not my playground.
 

ch33zw1z

Lifer
Nov 4, 2004
38,130
18,603
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I was responding to the topic, her209 created.

Are you trying to do something that will get me banned?

Yeah, you are.

digital-account-management-clever-girl.jpg

The topic was lattice mutliplication and whether or not the given problem was done correctly.

You didn't quote the OP, you quoted me. And none of my posts in this thread were about common core. So whatever conversation you guys were having, it didn't involve my posts. You just felt some need to post about how it's very easy to do lattice style, for what reason...who cares. My posts were very direct. I hadn't ever seen it, learned it today, post about it compared to the way I learned.

Done.