[Paladin2]

5 x 3 = 3 x 5

It's not just a good idea, it's The Law.

[W.]

The 'teachers' seem to be trying to make their students stupider.

Glad I learned the old-school way!

[rigelkentaurus]

this is stupid - seeing 5x3 as five groups of three and not 3 groups of five has nothing to do with learning calculus. If you don’t understand they are the same, you have zero hope of learning calculus anyway.

[Jeff Chandler]

This way of reading things, for instance, can be used when students learn matrices in multivariable calculus in high school.

Because so many American pupils take calculus in high school.

[FourPeas]

By the time one gets to multivariable calculus, the point is moot.

[timestax]

bump

[kjam22]

[Ingtar]

5 X 3 = 15 and should not need to be factored out if they were still memorizing their tables.

[Dr. Sivana]

I would like them to learn the Commutative Law of Multiplication before worrying about higher Calculus.

For the record, I took Calc 140s (mid level) in a college known to have a good program, and also known for NOT invoking grade inflation, and these matrices never came up. I also took Honors Calc in prep school, and they didn’t come up there, either. Admittedly, it was not my best subject.

[GraceG]

(5 + 5)=10
(10 +5)=15

Screw you common core, there is no “correct way” in math.

It is like thinking about the “climate” common core is a orthodoxy that is put in place to control HOW you are SUPPOSED to THINK.

Not “TO THINK”

[gop4lyf]

I teach 4th grade Math. This year at our Open House night, I had to prove to several parents that we don’t use Common Core lessons or curriculum. I don’t blame them. From what I’ve seen, Common Core math does nothing but confuse kids. I just started teaching them long division last week, and I shudder at the thought of my kiddos trying to learn it using Common Core strategies. If I won’t subject my own kids to it, I sure as heck won’t to other children either.

[Svartalfiar]

Hmm.. Under the commutative law, 5x3 = 3x5. So it's kinda an extra step 'show your work', but it's not wrong. Does common core not teach commutative, transitive, associative properties, etc?

This way of reading things, for instance, can be used when students learn matrices in multivariable calculus in high school.

Huh? I went to a private school, and was one of the more advanced ones. Taking a combined algebra/Pre-Cal class junior year, we had the option to take AP Calculus, AB or BC. But normal-track students didn't touch calculus, much less do much if anything with matrices. And as far as I can remember, matrix multiplication is the only time when axb =/= bxa. And I don't even remember the different between cross product and dot products.

[Fiddlstix]

I Thank God I went to school in the 1940’s

[laker_dad]

I have a BS in Mathematics from 1977. Went into computer programming and now I don’t remember much of the higher level math. But I do know my times tables...

[jsanders2001]

Common Core isn’tt about teaching the students knowledge. Its about teaching them how to think the way they are told to think by a higher authority without question. It is a method of programming minds to follow orders. In short, its brainwashing.

[PROCON]

But...but...did they ask the chillen how they feel about the numbers?

[Greetings_Puny_Humans]

Mathematically, both are correct. But under Common Core, you're supposed to read "5x3" as "five groups of three." So "three groups of five" is wrong.

[Terry L Smith]

I’d like to see this sort of reasoning being applied to a Boolean Logic question, or a Euclidean Geometry question.

[jimpick]

Gosh I better get my kids back in public school. I have been teaching them all wrong.

[onedoug]

Down with the commutative law!