Why is 5+5+5=15 Wrong on Common Core Test

What is 5x3? 15 right. Why is 5+5+5=15 on Common Core math tests wrong.

[Ashstrodamus]

I would've put 7.5 x 2 just to fuck with the teacher.

[AlienRelics]

I had poor teachers like that. I remember correct answers marked as wrong because "we haven't learned that way yet." So students are penalized for being smart! This was long before "common core".

[thejuiceweasel]

The fact that the kid used common sense to make the much shorter derivation of 5+5+5 shows that he clearly understood the problem *and* is probably not a lost intellectual case like the people that came up with this nonsense.

[hirodsrling]

Imagine if Newton just got told "sorry we don't do it that way" when he created calculus to better find certain results

[Getvagazzled]

my life is too fucking short for this bullshit

[alfredodelacruz]

I thought this was going to be a mind blowing lesson about why 5 plus 5 plus 5 is not 15

[wbjeg]

As a full-time Asian, this absolutely disgusts me.

[BaremetalBaron]

The great irony is that they're marking students wrong for something that shows that the kid actually understands the material and is capable of improvising with it. If the student can only follow the steps by rote exactly as you have specified at all times, then there's a very good chance they don't understand and can't apply the information to novel situations.

But worse, I would argue that "5*3" is grammatically ambiguous about grouping. The way *I* have always read "5 times 3", I interpret it more like "5 multiplied by 3", not like "3 groups of 5". Indeed, interpreting the phrase "5 times 3" to mean "3 groups of 5" sounds like archaic and stilted old-timey English to me, and does not roll off the tongue at all. So if I were one of these knuckleheads who thought it mattered which way they grouped it, I probably would have marked the *other* answer as incorrect.

But seriously, there is no "correct" grouping of 5x3 in the abstract. To mark them wrong here is just factually wrong, because the commutative property is a fundamental algebraic relationship.

Getting pedantic about notation with 8 year olds to trip them up with technicalities is just sick, especially when that notational quirk is just an arbitrary convention chosen at random and is in no way implied or infer-able from the usage of that notation, and doesn't even affect the result. Again, I would argue that what the child did is more intuitively correct.

[ratshitstrap]

"Johhny has 3 apples, he eats 2 of them. Calculate the radius of the moon using only a paperclip and this information. You may not step outside between 7:00pm and 6:00 am for reference of any sort"

[snakesocks]

It's a commutative law of algebra that A*B = B*A

[krispibean]

Common core is basically the education system getting mad at you for being smart and taking shortcuts while they're the ones being dumb and doing things in unnecessarily complicated ways.

[biggreentruck]

I've always read "5x3" as "5, 3 times", which would be 5+5+5. Conversely, I would read "3x5" as "3, 5 times", or 3+3+3+3+3.

Not that it matters; you get the same answer, either way. Every single example that I have seen from the Common Core system, shows me that they have overly complicated simple math. Simple math needs to remain simple. It is the foundation for the more complicated math. If students of the more complicated math do not have the comfort of the simplicity in the simple math, if basic addition has been made overly frustrating, how will they learn the complex stuff? And, if they can't learn the complex stuff, God help us when we have no competent engineers in 20 years!

Whoever came up with this nonsense, clearly holds a position of no importance, and had to create this asininity in order to justify his own existence. He should be promptly horse whipped, at noon, in the middle of the town square. So should the nitwits that pushed this garbage into the school system.

[hayesscarbrough]

This is why I hate common core. This kid was just thinking for themselves and got marked wrong because they didn't do it how the teacher wanted. This somewhat happened to me in Algebra 2. We took a test and when we got it back I had made a 40 on the test even though I only got one problem wrong. The teacher said it was because I didn't work it out how she wanted me to.

[niboe]

I feel kids could get the wrong idea with a scoring system like this. They might think 3x5 does not equal 5x3.

[chiffmonkey]

Visually a 5x3 and 3x5 rectangle are THE SAME RECTANGLE because which axis is X and which is Y has not been defined.

[brandonkey]

"You wont always have a calculator with you"
Well thats where youre wrong

[stephaniejoobern]

It's wrong because the person who was grading it just lost all their money gambling and needed to take their frustration out.

[KX]

The Commutative Property is a fundamental of mathematics. a.b = b.a
The 3rd grader instinctively knew this because it's so obvious, even if they don't know the name for it. By marking this answer wrong, the teacher is essentially teaching a child that the commutative property is wrong, which is fucking indefensible.

[michaelparker]

Maths should be about finding the solution the most efficient way possible and not about complicating that process to get the same result.

[whiteraven]

Things like this make me happy that I chose to homeschool my children.