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

[SamQuint]

This is that stupid common core bullcrap.

I have seen where teachers will mark 5+5+5 wrong and the correct answer is 3+3+3+3+3.

So tell them the right way is 5 X 3 is saying 5 times 3 or 3 repeated 5 times.

if the question was 3 X 5 it would be 5 ,3 times. even though both are the correct answer, the lame ass teacher will only accept the common core solution. total bullcrap

This is of no use at all. Should just memorize the multiplication tables up to the 12s like we used to in the good ol days.

 

[dullard]

This is that stupid common core bullcrap.

The OP is from Florida, which if I Googled correctly doesn't use the common core. So how is your post even remotely relevant?

 

[Humpy]

Actually you "breathe" air. "Breath" is air that is expelled during breathing.

Does one not inhale a breath of air?

In before 10 page thread.

 

[CraKaJaX]

Did you have anything meaningful to post? Is there something specifically wrong with common core that you want to discuss, or are you just bashing it since it is the political hot-topic of last year? It sounded far more like you were a political hack (attacking the Republican's Common Core idea, even though the Republicans are now against it because Obama was for it) rather than actually contributing.

I'm about as far from caring about P&N bullshit as you could possibly get. I'm sorry if this got under your skin. You are obviously pretty bitter over nothing that was intended. Maybe you woke up on the wrong side of the bed. Maybe you -really- care about your beliefs. Maybe I did ask about apples and staplers and just completely forgot - in which case your argument is valid. Whatever the case may be, have a great day!

 

[Brainonska511]

This is of no use at all. Should just memorize the multiplication tables up to the 12s like we used to in the good ol days.

Rote memorization, that's surely worked out well...

The idea is to get children to internalize exactly what is happening in the mathematical operation and be able to recognize situations in which multiplication can be used, as math word problems present themselves all over life.

As to the OP's statement problem: it's presented as 5 groups of 3 likely because it's read from left to right. Since they are in the learning stages, I think it's appropriate to stay consistent until the concept is internalized.

 

[dullard]

I'm about as far from caring about P&N bullshit as you could possibly get.

I'm not bitter, I'm trying to actually make the world a bit better, one person at a time.

Common core isn't the problem and isn't a disaster like you said. The problem is poor teaching, over testing, and lack of understanding from everyone involved.

Lets attack the real problems. I'd rather go after poor teaching than just let blanket statements like the ones from you and SamQuint go by. Kneejerk blanket statements bashing Common Core don't help anyone and aren't constructive. I wouldn't be surprised if even more people chime in complaining about Common Core when that has nothing to do with the problem.

Let teach that both multiplication orders (relating to the OP) are correct and both are useful. Then lets teach them how to create either order from actual problems, why one order may be more useful in some cases than others, and even more importantly how to use the results.

 

[Schfifty Five]

I know both end up the same result, but I agree with OP that it feels more natural or logical to read it as 5+5+5.

 

[ElFenix]

yes but only because English is horribly inconsistent with how things are done

that's to keep out the riff raff

 

[kranky]

I'm conflicted. I'm very used to seeing multiplication as appended to the first number like the OP does. We write things like "x3" after the number we want to multiply, not in front of it.

But if you were just learning math, and were taught that you read a multiplication sign as "groups of", you'd see it the other way. In that case "5 groups of 3" would seem very natural.

inb4 "this x1000!"

 

[IronWing]

"this x1000!"

Can you diagram that for us?

 

[dullard]

I'm conflicted. I'm very used to seeing multiplication as appended to the first number like the OP does. We write things like "x3" after the number we want to multiply, not in front of it.

I still disagree.

We say five dozen eggs as 5 x 12 (the 5x multiplier before, as in 5 groups of 12). We don't say a dozen eggs times five as 12 x 5 (the 5x multiplier afterwards).

We say 3 weeks as 3 x 7 (the 3x multiplier before, as in 3 groups of 7 days). We don't say weeks times 3 (the 3x multiplier afterwards).

If you really think about it, we almost always put the multiplier first. The result is the same, but as we speak it in English we put the multiplier first. So it is far easier and less confusing to the child to also write the multiplier first. And if you get into coding, it is far easier to follow if the multiplier is first.

Think about subtraction. x - 5 = x + -5 = x + (-1 * 5). It just makes more sense then looking at it as x - 5 = x + -5= x + (5 * -1). Why would you suddenly throw the minus sign to the end? It works, but why keep rotating things around? The minus sign started in the middle, it should stay in the middle.

 

[rh71]

multiplication taught in 1st grade? Wow I thought FLA had bad schools in general? I believe we officially start in 3rd grade here, though they've been doing groupings like that since 1st.

As for the question posed, does it say your way is wrong anywhere? I don't think it would since multiplication is reversible - they just worded it that way to make it read left-to-right.

 

[TheGardener]

Need a fourth choice on Poll. "The kid is learning. STFU and be thankful."

 

[radhak]

5 x 3 is always read aloud as "5 times 3", which in its simplest form means, replicate 3 five times., or is akin to the sentence "this class has five times as many students as that, which has only three, so this class has 5 times 3, ie 15". So, the school is right: 5 x 3 = 3 + 3 + 3 + 3 + 3.

That said, anybody who marks the other way (5 + 5 + 5) as wrong, needs to be shot, quartered and buried. And I hear you might see that anal approach in Common Core.

(Yes, Florida follows Common Core, woe is us).

 

[rh71]

We say 3 weeks as 3 x 7 (the 3x multiplier before, as in 3 groups of 7 days). We don't say weeks times 3 (the 3x multiplier afterwards).

People also tell time by saying half past 1, or a quarter to 1, which is just making more work than necessary.

 

[feralkid]

Get off my lawn x 1000.

 

[tynopik]

I don't have kids, but I do know that the common core ways are a disaster.

because some facebook post told you so?

 

[zinfamous]

3 groups of 5 is superior to 5 groups of 3 because it's a better springboard for understanding and manipulating numbers.

First teach the kid to think of numbers as groups of 5s or 10s--very easy to work with once they get the hang of it. 3 is a weird base number that is only favored by strange people like the Finnish.

Memorizing multiplication tables like we did in childhood is clearly a stupid method and doesn't teach anyone anything. It might prepare you for a lovely career at Foxconn before being replaced by a robot arm, but that's about it.

 

[Paladin3]

I didn't read the entire thread, but really hoping your kid said "it's the same thing either way, Dad, why are you making such a fuss?"

 

[crashtech]

It's semantics, really. Replacing the multiplication symbol with the phrase "groups of" results in 5 groups of 3.

 

[Ruptga]

3 groups of 5 is superior to 5 groups of 3 because it's a better springboard for understanding and manipulating numbers.

First teach the kid to think of numbers as groups of 5s or 10s--very easy to work with once they get the hang of it. 3 is a weird base number that is only favored by strange people like the Finnish.

Memorizing multiplication tables like we did in childhood is clearly a stupid method and doesn't teach anyone anything. It might prepare you for a lovely career at Foxconn before being replaced by a robot arm, but that's about it.

Agreed and agreed, but you're wrong about multiplication tables for the same reason you're right about the other two things. Knowing them up to 10x10 (or 9x9 since 10x10 is trivial) is handy because you can immediately break something like 18x8 down into 10x8 + 8x8 and find the answer with just a one addition operation. Counting out 18, 36, 54, etc works but is much slower and more prone to errors because of the greater number of steps involved. That should only be used at the very beginning as a way to help them develop a concept of how multiplication works.

 

[SKORPI0]

It's like saying 5 sets of triplets, so there are 15 individuals. :sneaky:

More rare are 3 sets of quintuplets, but still 15 individuals.

 

[MongGrel]

Florida doesn't need common core, they are already at that level - see "Florida Man"

Ah, more Florida bashing, why is it even necessary ?

 

[Jaepheth]

They're both the same.

Three groups of 5 seems easier because we use a base 10 system and 5 is a factor of 10.

Thus making counting by 5s always end in 5 or 0 as you all know (5x2 =10; so counting by 5s has 2 "stops" or possible last digits, and counting by 2s has 5; in base 8 counting by 2s would have 4 different last digits because 2x4=10 (or 8 in base 10)). 3 and 10 are relatively prime; so when you count by 3s the last digit will run the gamut of all digits before repeating.

So having children do it the harder way may be a better math exercise; learning to do things efficiently usually comes after having a thorough understanding of the subject at hand.

 

[KeithP]

Multiplication is commutative. You're both right.

You are answering the wrong question. It wasn't about how to get the correct answer, it was about the text book's english interpretation of the problem which, as described, is wrong.

I believe the order of operations rule that applies here is that when you have operations of the same rank, you move from left to right. Using that rule the only correct english interpretation of 5 x 3 is five three times. In other words 5 + 5 + 5.

To describe it as three five times you have to read the equation from right to left which would be in violation of the order of operations.

Here is another math problem that parents are faced with all time:
public schools + kids = idiots

-KeithP