Stupid 'new' math question - am I right or wrong here?

[slayer202]

5+5+5 is shorter, thus faster and superior.

it's easier too

everyone saying "both are right" are assholes. that's not the point, morons

 

[JTsyo]

I have an idea. Let's teach everyone postfix notation! It gets rid of parentheses, plus it reads this problem unambiguously.

5 x 3 in postfix is "5 3 x", or "five three times".

HP calculator way?

 

[DeathReborn]

5+5+5 makes sense with currencies, hardly any (if any) legal tender uses 3p/c coins.

That whole 20x1 thing... I am pretty certain most kids will miscount all those 1's and get it wrong anyway. Talk about giving them more work to do.

 

[zinfamous]

Common Core: the new bogeyman from the people that brought us "death panels".

I love when people blame the "common core" boogeyman without understanding what it is. It is a set of educational standards dictating the educational concepts that must be taught, it is not the specific curriculum that is used in teaching those concepts. There are many different curriculae approved to meet valid standards and they all teach those standards differently. If you take umbrage with how 5x3 or some other concept is being taught don't blame common core, blame the curriculum peddler.

Beyond that this thread seems to be a whole bunch of "it was better when I was a kid" moaning. How many of you learned to add multiple numbers by aligning them vertically then adding from right to left while carrying values in excess of 9? Most experts will tell you that it's much faster to add left to right instead.

Without the drunken lazy Irishman, the lecherous Italian, the shifty Jew, or the evil darkie to latch one's prejudices and life miseries to, the current crop of over-protective middle class and lower class parents must now turn their gaze towards policy and paradigms that are, one might argue, far more insidious to the common culture than a skin color or native culture might be. Better a source of exterior blame than an internal examination of personal failures if little precious is somehow failing to meet basic standards.

(well, it's more tolerant and "PC" to do so, anyway. Fortunately for us, we no longer have to worry about this "PC nonsense!" because our Trump messiah is now here to rescue us from this. With any luck, the shifty Jew and now the stinky brown people will regain their prominent position as the central necessary fear of god-fearing WASPS that are the only true masters of this blessed land of ours)

 

[Humpy]

I love when people blame the "common core" boogeyman without understanding what it is. It is a set of educational standards dictating the educational concepts that must be taught, it is not the specific curriculum that is used in teaching those concepts.

That's what the thread is about though.

The common core standards dictate concepts, in this case the concept of groups to teach multiplication and division. The concepts, for whatever reason, are then implemented in a variety of ways, some of them are humorously absurd.

Groups are one of several fine ways way to explain the idea, that doesn't seem to be an issue. It's more the rigid use of the standards leading to silliness like one of two equivalents being considered wrong while the other is right.

Blame can be placed nearly anywhere but there is no reason to exclude common core from the discussion.

Anyway, let's just be thankful for private schools.

 

[Humpy]

Without the drunken lazy Irishman, the lecherous Italian, the shifty Jew, or the evil darkie to latch one's prejudices and life miseries to, the current crop of over-protective middle class and lower class parents must now turn their gaze towards policy and paradigms that are, one might argue, far more insidious to the common culture than a skin color or native culture might be. Better a source of exterior blame than an internal examination of personal failures if little precious is somehow failing to meet basic standards.

(well, it's more tolerant and "PC" to do so, anyway. Fortunately for us, we no longer have to worry about this "PC nonsense!" because our Trump messiah is now here to rescue us from this. With any luck, the shifty Jew and now the stinky brown people will regain their prominent position as the central necessary fear of god-fearing WASPS that are the only true masters of this blessed land of ours)

So many trigger words in one post. I am freaking out.

 

[zinfamous]

So many trigger words in one post. I am freaking out.

 

[dave_the_nerd]

Twenty-five-ish years ago, we were taught that a multiplication sign could be read as "of."

So, "5 x 3" is "5 of 3" which would be 3 + 3 + 3 + 3 + 3.

If you use "times" instead, it's still "5 times 3" or "three, five times." So again, same thing. (If you read "five times three" as "5 + 5 + 5" you're just skipping to the end because, guess what, you already know this stuff.)

I think the "this is right, the backwards way is wrong" is less about being right or wrong, and more about learning a certain thing a certain way to make sure that knowledge is accompanied by understanding. Which is hard to determine when you're dealing with kids who supposedly have never been exposed to a concept before. (Since it's, like, second nature to us oldsters.)

But doing it backwards will get you there too. Just like anything else - learn the rules first, then learn when to break them.

 

[crashtech]

The commutative property should be (and might be) integral to the lesson of which the OP posted only one sample, the problem in question is likely just one of the learning steps, taken out of context, it can easily look ambiguous or even nonsensical.

 

[Humpy]

It's possible that this is all just a small part of a successful master plan.

I'm skeptical when the path contains this kind of stuff:

Use the repeated addition strategy to solve: 20 x 1

Something has led people to believe that teaching multiplication as 20 groups of 1 is correct while 1 group of 20 is incorrect.

Regardless, it seems like a strange step to take on the way to: Forwards or backwards does not exist. It's equivalent.


I liked this picture because it didn't crop out problem #3 like a lot of others did. There is a simple logic that builds on the earlier two. So maybe it's not all that bad.

 

[Brainonska511]

Twenty-five-ish years ago, we were taught that a multiplication sign could be read as "of."

So, "5 x 3" is "5 of 3" which would be 3 + 3 + 3 + 3 + 3.

If you use "times" instead, it's still "5 times 3" or "three, five times." So again, same thing. (If you read "five times three" as "5 + 5 + 5" you're just skipping to the end because, guess what, you already know this stuff.)

I think the "this is right, the backwards way is wrong" is less about being right or wrong, and more about learning a certain thing a certain way to make sure that knowledge is accompanied by understanding. Which is hard to determine when you're dealing with kids who supposedly have never been exposed to a concept before. (Since it's, like, second nature to us oldsters.)

But doing it backwards will get you there too. Just like anything else - learn the rules first, then learn when to break them.

Yep. It's about conveying an understanding of what's being done with the math to children who are just starting to learn it. But that conversation seems to be totally lost here with the "I know better" crowd.

 

[edro]

Ah, a snarky reply! 4/10 attempt, but I still like it.

That's what's nice about the visualization of units, it demonstrates the relation of addition and multiplication in one simple picture, as well as other basic concepts like calculating area and spatial logic by rearranging and dividing the units.

I was actually wondering if it is still taught that way. Maybe someone else knows.



I guess to me the big picture is bigger than understanding someone's idea of what 5x "means".

I'm with Humpty

 

[edro]

I liked this picture because it didn't crop out problem #3 like a lot of others did. There is a simple logic that builds on the earlier two. So maybe it's not all that bad.

Ah, well yes, if you use that English sentence "7 packages of cupcakes with 4 in each package" then yes, it is 7x4.

For me, it is intuitive that 5x3 is:
[The Number 5] times 3 groups

but I can totally understand if some people intuitively say 5 groups of 3.

 

[Humpy]

Ah, well yes, if you use that English sentence "7 packages of cupcakes with 4 in each package" then yes, it is 7x4.

For me, it is intuitive that 5x3 is:
[The Number 5] times 3 groups

but I can totally understand if some people intuitively say 5 groups of 3.

I think the test taker (if legit) pretty clearly understood the word problem and would have also been okay with "A package contains 4. Julie bought 7 packages. How many?".

That the first two problems were done "wrong" while the third was correctly understood makes the strictness of the teaching method appear pointless.