Is this a "common core" problem?

[Aragarthiel]

Yes, it does make "five groups of three" wrong. Because it is.

You do know "Because it is" really isn't a legitimate reason, right? WHY is it? Because you weren't taught that method? That doesn't make it wrong.

[Gravekeeper]

-but everyone hates it cause it's different.

^ That right there.

Irrelevant to the discussion. The fact of the matter is that 5 x 3 is NOT "five groups of three". It is, in fact, "three groups of five".

It is completely relevant to the discussion. You can't rant away about the lesson and then say that the lesson is irrelevant. And no, that is not a "fact". That is just one way of solving the problem.

For the umpteenth time, this is an alternative method of problem solving designed to prepare a student for more advanced math. Just because you personally don't like it doesn't mean shit in the grand scheme of things. Improving education standards isn't being done solely to please you specifically.

So if you have any actual, real argument beyond "I don't like it so its wrong" by all means. Otherwise, lets move on to something actually relevant.

While true, the mathematician (with a PhD, I might add) who was originally supposed to be a part of developing the math part of the CC said he couldn't endorse it once they got done with it. I think that's mentioned in one of the videos.

No, he didn't and no he hasn't. Like many of the CC authors, what he's frustrated with is how CC was turned into a political talking point and how difficult the implementation of CC has been as a result.

And btw, his name is Jason Zimba since you can't be bothered to do even that much research into your own argument.

Does it really matter? The bottom line is students AND parents are struggling with this.

Yes, it does because otherwise you're just throwing a bunch of shit out like it proves anything without even articulating what it is you're trying to argue to begin with.

You've been ranting about this for a couple of pages now and yet don't even seem to know what CC is let alone who created it or how. But somehow you seem to think you're qualified enough on the subject to tell us what is or is not wrong math.

[Kheldarson]

Or maybe this:

Subtract 270 from 530.

Again, most of us would just do this:

530
-270
-----
260

Which is not, supposedly, "Common Core Friendly", even though, again, the answer is correct.

The "common core" way is to add 30 to both numbers first, ending up with 560 and 300, and THEN subtract..

That's brilliant though! You bring one number up to an easy to subtract number and you can do it in your head at that point! Fuck, I do that all the time: I have a jacket that's normally 99, I can get it for 46.48, 46.48 is basically 46.50, so 99.02 for the jacket, I'm saving 12.52 because I brought it to easier numbers to manipulate in my head.

Why is that wrong to teach?

[TheHuckster]

mjr, just to set the record straight, what you're saying is had the opposite happened, and the student had answered 5 x 3 with 3 + 3 + 3 + 3 + 3 and the teacher marked that wrong and corrected it with 5 + 5 + 5, you'd be perfectly fine with it because 5 + 5 + 5 is, as you say, "the correct way"

And the reason that 5 + 5 + 5 is the correct way and 3 + 3 + 3 + 3 + 3 is the "wrong way no matter how you slice it" is "because it is."

I just want to make sure I have this correct.

I mean, I do think the teacher was picky in the correction, since the student used the same prescribed method, just in a different order, but it sounds like you're saying there's only one correct order, rather than two equally valid orders.

Again, most of us would just do this:

530
-270
-----
260

You are leaving out some very critical steps in that problem. If you had actually taken the steps that were prescribed in the "old math" you'd likely find that there was just as many steps to arrive at 260 as the "new math" way. You don't just take 530-270, put it in a column layout and then magically get 260.

I'm not saying that the new way (or the old way) is better or worse than the other. But I bet you if we lived in a parallel universe where the "new math" were the status quo and the "old math" was what was introduced, we'd have just as many people up in arms about how the newfangled way with borrowing numbers and stacking them on top of eachother is really confusing and also some veiled attempt at having kids practice witchcraft and become communists when they grow up.

This is a good explanation (read accepted answer). Basically, they are introducing this in addition to a few other strategies to do simple math in your head. Some strategies work better than others depending on the numbers involved and what you're trying to figure out.

Frankly, I wish they had done a lot more of mental strategies when I was in school, instead of spending 90% of the time having us do paper-and-pencil math. We did do a few mental strategies, but not nearly enough.

[mjr]

You do know "Because it is" really isn't a legitimate reason, right? WHY is it? Because you weren't taught that method? That doesn't make it wrong.

Ok, I'll play.

Why is 2 + 2 = 4? No matter how hard I try, I can't make it equal 1. Or six.

And simply because I wasn't taught a method doesn't make it right, either.

[mjr]

It is completely relevant to the discussion. You can't rant away about the lesson and then say that the lesson is irrelevant.

I'm not saying the lesson is irrelevant. I'm saying your question to me regarding solving the problem is irrelevant.

That is just one way of solving the problem.

In an incorrect fashion, sure.

For the umpteenth time, this is an alternative method of problem solving designed to prepare a student for more advanced math.

And for the umpteenth time, I've said, that alternative method is WRONG.

Improving education standards isn't being done solely to please you specifically.

I never said it was. This, however, doesn't seem to be "improving" them. You can scream about how "people don't like it" all you want, and believe it's because people are "unfamiliar" with it. That may well be true, but I think that's a SMALL number of people, and most of the ones that don't like it do so for good reason.

Help your kid with his homework, get the questions right, and have the worksheet come home marked with red because you wrote a correct answer, but it wasn't "Common Core" friendly, and then we'll see how you feel.

"I don't like it so its wrong"

Hardly what I said. It's not "I don't like it so it's wrong". The argument is, AGAIN, "It's wrong because it's wrong."

No, he didn't and no he hasn't. Like many of the CC authors, what he's frustrated with is how CC was turned into a political talking point and how difficult the implementation of CC has been as a result.

Then why didn't he sign off on the final product?

And btw, his name is Jason Zimba since you can't be bothered to do even that much research into your own argument.

Knew that, just didn't think it was relevant.

Yes, it does because otherwise you're just throwing a bunch of shit out like it proves anything without even articulating what it is you're trying to argue to begin with.

I know exactly what I'm arguing, and I've articulated it quite well. Why the anger?

The simple FACT of the matter (and I can't believe I'm having to state this AGAIN) is this:

5 x 3 is NOT (per the way the question is worded) "three groups of five".

You've been ranting about this for a couple of pages now and yet don't even seem to know what CC is let alone who created it or how. But somehow you seem to think you're qualified enough on the subject to tell us what is or is not wrong math.

You seem to be the same way. It was set up to look like it was "state led" when in fact it was not. The five main people involved in writing it were David Coleman, William McCallum of the University of Arizona, Phil Daro, and Student Achievement Partners founders Jason Zimba and Susan Pimentel.

In fact, here are the eight "standards":

Make sense of problems and persevere in solving them.
Reason abstractly and quantitatively.
Construct viable arguments and critique the reasoning of others.
Model with mathematics.
Use appropriate tools strategically.
Attend to precision.
Look for and make use of structure.
Look for and express regularity in repeated reasoning.

Tell me where the "grouping" thing falls in here.

[TheHuckster]

Ok, I'll play.

Why is 2 + 2 = 4? No matter how hard I try, I can't make it equal 1. Or six.

And simply because I wasn't taught a method doesn't make it right, either.

Wait, are you telling me that 5 x 3 being 3 + 3 + 3 + 3 + 3 is as wrong as saying 2 + 2 = 1?!

In terms of "correctness" this is more analogous to finding a circumference of a circle by multiplying PI times the diameter rather than PI times double the radius. They're both equally valid methods, but depending on what information you have about the circle one might be better than the other.

[mjr]

That's brilliant though! You bring one number up to an easy to subtract number and you can do it in your head at that point! Fuck, I do that all the time: I have a jacket that's normally 99, I can get it for 46.48, 46.48 is basically 46.50, so 99.02 for the jacket, I'm saving 12.52 because I brought it to easier numbers to manipulate in my head.

Why is that wrong to teach?

I do that in my head, too. That doesn't mean I should be marked off for it if I, for some reason, don't show that I did it on paper.

I don't get what's hard to understand about that.

Until you get a number like 769 - 554.

Then what do you do?

My main quibble is what is called a "group" in the problem. "Three groups of five" is BACKWARD (by any definition) compared to 5 x 3.

[mjr]

Wait, are you telling me that 5 x 3 being 3 + 3 + 3 + 3 + 3 is as wrong as saying 2 + 2 = 1?!

No.

What I'm saying is that calling 5 x 3 "three groups of five" is wrong, no matter how hard people want to make it right.

Again: 5 x 3 is 5 + 5 + 5.

If you want 3 + 3 + 3 + 3 + 3, you need to write 3 x 5.

[TheHuckster]

No.

What I'm saying is that calling 5 x 3 "three groups of five" is wrong, no matter how hard people want to make it right.

Again: 5 x 3 is 5 + 5 + 5.

If you want 3 + 3 + 3 + 3 + 3, you need to write 3 x 5.

You're arguing arbitrary semantics. There's no scientific or mathematical reason what you're saying is The Truth. "Three groups of five" is wrong to you because someone once told you it's wrong. It doesn't mean if someone else says that's how they think it makes them wrong.

I get paid monthly. Know what I do sometimes? I take the paystub, look at my withholding, and then do $X x 12 to figure out how much federal withholding I have for the year.

But, and you're going to HATE me for this, other times I do 12 x $X.

Yet, either way, I think of it as $X + $X + $X + $X + $X + $X + $X + $X + $X + $X + $X + $X

[mjr]

You're arguing arbitrary semantics.

I'm arguing the semantics of the question.

This:

XXX
XXX
XXX
XXX
XXX

is five groups of three.

This:

XXXXX
XXXXX
XXXXX

is three groups of five.

The first one is 5 x 3.

The second is 3 x 5.

I get paid monthly. Know what I do sometimes? I take the paystub, look at my withholding, and then do $X x 12 to figure out how much federal withholding I have for the year.

But, and you're going to HATE me for this, other times I do 12 x $X.

Yet, either way, I think of it as $X + $X + $X + $X + $X + $X + $X + $X + $X + $X + $X + $X

That's not relevant to what I'm talking about. I'm simply stating that the groups are named wrong in the initial problem. And it's WRONG that the kid got marked off for writing 5 + 5 + 5.

[s_stabeler]

again, we are talking about third-graders- frankly, at that level, as long as they use a method that consistently gets the right answer, I don't think it actually matters if they are adding up 3+3+3+3+3 or 5+5+5. The actual question said: use the repeated multiplication problem to work out 5 x 3.

is it useful for higher maths to know the difference? possibly- I don't think I've ever done any where it matters. That can be addressed at a higher level. Let's teach the kids how to get the correct answer first, before we worry about teaching them to pick the right method between several different ways of calculating the answer.

[TheHuckster]

I'm arguing the semantics of the question.

This:

XXX
XXX
XXX
XXX
XXX

is five groups of three.

This:

XXXXX
XXXXX
XXXXX

is three groups of five.

The first one is 5 x 3.

The second is 3 x 5.

I don't see it that way. Because the standard way to measure things is width X height, I think of 3 x 5 as 3 columns of 5 rows. In spreadsheets, you identify a cell by column first, then row. Horizontal, then vertical. That's the standard.

That's not relevant to what I'm talking about.

Yes it is relevant. I'm grouping my monthly income into 12 months (i.e. groups), therefore by your own semantic rules, it is wrong for me to express it as 12 x $X.

[mjr]

again, we are talking about third-graders- frankly, at that level, as long as they use a method that consistently gets the right answer, I don't think it actually matters if they are adding up 3+3+3+3+3 or 5+5+5. The actual question said: use the repeated multiplication problem to work out 5 x 3.

Then the teacher should not have marked it wrong.

QED.

[mjr]

I don't see it that way. Because the standard way to measure things is width X height, I think of 3 x 5 as 3 columns of 5 rows. In spreadsheets, you identify a cell by column first, then row. Horizontal, then vertical. That's the standard.

Well, in software design, you do rows first in an array. And honestly, it makes sense logically. How do we read? We read left to right, top to bottom.

So rows and columns makes sense.

Yes it is relevant. I'm grouping my monthly income into 12 months (i.e. groups), therefore by your own semantic rules, it is wrong for me to express it as 12 x $X.

No, because you're not grouping the months into groups of income.