Controversial math problem. Why was 5x3 = 15 marked wrong?

The internet went crazy over this problem...but there is more to the story than the media reported.

References
Euler Elements of Algebra originally published 1765
Euclid Elements Book VII (around 300 BCE)
cover
Multiplication and repeated addition

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[ErikYoungren]

There's nothing wrong with teaching multiplication as repeated addition. However, I have a HUGE problem with potentially teaching people that 5x3 is not equal to 3x5.

The problem is that the question is not a math question, is a "follow the instructions" question that is in math format

[Hitarth_Rana]

"5 times 3" can be interpreted as both "5 times, 3" and "5, times 3". Accepting only one of them coz the book said so it's killing logical thinking required to do mathematics

[TheMattastic]

This feels like a system designed to make a generation of children innumerate.

[hdjong]

I state that 5 x 5 is not the same as 5 x 5

[dazartingstall]

Yes it's repeated addition. But if you insist on the strict adherence to multiplier × multiplicant, good luck with ½ × 5 using this method.

[PolygonSwan]

"600 x 3" hang on, be right back.

[GabrielMartinFlores]

But what is the PRACTICAL VALUE of such a distinction in real life?!?

[VladimirE.-isee]

And this is why kids end up hating math.

[Ken-ercq]

The student is correct. They have used repeated addition, just that they have chosen to reverse the order. What we want to do in maths is to reward students that find an easier way to answer the question. What the teacher is saying is there is a fixed rule to do this, and you must follow this rule. The main point of the question is to discover if students understand what multiplication is, and either answer does that.

[ericbarlow]

I was taught it was repeated addition but was also taught that 5x3 is the same as 3x5, ergo, both 5+5+5 and 3+3+3+3+3 are both valid.

[Haispawner]

The fact that people are DEFENDING this dictatorial self-defeating BS way of teaching here in the comments is so wild.

I hope none of them apply to be teachers.

[justinlloyd]

This is how you make students disengage from math.

[kvf]

If we're going into semantics here, the question doesn't ask to use only the repeated addition strategy. The student used commutativity and the repeated addition strategy. So even with that interpretation he was correct.
Besides, in paragraph 27 of the very same chapter of Euler's book he writes: "It may be farther remarked here that the order in which the letters are joined together is indifferent; ... for 3 times 4 is the same as 4 times 3."

[SirMerenos]

The question is why does math at a low level need to go into semantics?
This is why so many people hate math these days
Instead of teaching it as a puzzle to be solved, it is presented as trick questions where the end result doesn't matter so long as the process is as ordained.
If this was college level, then sure it makes sense to go into the semantics, but at 2nd grade where this is supposedly taught, the focus should be on engaging children with math and teaching them to love numbers, not hate numbers.
5×3=3×5
So I argue it should have been allowed

[christianbolt]

As someone who taught mathematics at a university, it makes me mad when definitional games get in the way of actually solving a problem.

[jefffixesit]

For me, this is an arbitrary assessment that has no place in 3rd grade mathematics. The commutative property of multiplication is far more important to learn than insisting on an arbitrary ordering of multiplier and multiplicand. ❤

[harshgada]

Why does school teachers have a " Ur answer is correct, but u didnt use my method, so i will give it wrong " attitude.

[abigfavor]

No, still mad. 5+5+5 is valid. Imagine trying to teach 2xA as two groups of A but Ax2 as A groups of two.
It's trying to confuse kids on purpose

[MaybeFactor]

This is all good and well, except that 5*3 = 3*5 = 5+5+5
The student simply skipped writing down the absolutely trivial step of swapping the order of the numbers being multiplied. They DID demonstrate usage of the repeated addition strategy