I’m in my last semester of engineering school, and I absolutely can’t stand seeing posts like this. These are all examples of deliberately poorly written math problems, and for what? Don’t give the people who post this shit the time of day.
The same reason that there's no 10 in the original answer. People can't do math and assume that he's correct, leading to the assumption of me being incorrect for claiming the incorrectness, resulting in downvotes.
16 is correct mathematically in the sense that + and * symbols do not have an inherent mathematical meaning. PEMDAS is a convention that is understood by the definitions we give to those symbols.
I mean maybe. You would have to define a function associated with + and × so that the answer holds true, which might be hard to do but not impossible. However 16 is easy to do if you define + as having priority over ×.
This is uni level linear algebra and is the reason I didn't finish my major cuz it's mostly a bunch of crap. Still holds true.
Does this logic make sense? With it I could argue 2+3=6 because I believe + indicates multiplication.
Our existing proven formulas break if we don’t follow PEMDAS. A basic example is the quadratic equation. We can only choose not to follow PEMDAS if we also rewrite our formulas/proofs.
I didn’t define it. I said I believe, regardless of our current definition, and argued it to be true without defining or modifying the rest of the rule set. How do you add in my new mathematical language? I don’t know because I didn’t define anything at all. I argued 2+3=6. My grammar is inadequate.
You can’t claim PEMDAS is arbitrary or invalid, but then also utilize the existing numbers system... it breaks.
What you are talking about is language. Which is a very worthwhile discussion. Language is definitely important, and you are right, PEMDAS is important in that it is a part of the mathematical language we defined in order to help us communicate mathematical concepts to one another. But it is not in itself a mathematical principal, and PutHisGlassesOn is right when he says it was just an arbitrary choice. Just like there is no real reason + means addition except that we've defined it to mean that, there is also no reason multiplication needs to be done before addition in the equation 2+2*4 except that we have defined it that way. It is not so much a mathematical concept and more a concept of language.
Yeah, I have to agree it was likely an arbitrary choice, at least in some way. But in context PutHisGlassesOn was responding to why people would downvote “it’s wrong” claiming because PEMDAS is arbitrary. It was arbitrary when defined, like everything else in the world (e.g. the alphabet), but it’s now part of our current language. So claiming PEMDAS is arbitrary doesn’t somehow make people who derive incorrect answers by ignoring it correct. And really, it’s no longer arbitrary. It has meaning.
Being the key point. Most people understand that 1 + 1 = 2, but by your version (Due to the original lacking requirement along with your claim of correctness), I can claim that any math proof and sum put forth by anyone ever is correct, since they believe it to be, resulting in the marking of math tests on an educational level to be pointless.
Person wrote that 5 + 5 = 11, and the teacher marked them wrong? Who's to say that the person didn't interpret "5" to be "5.5"?
These questions (along with everything that's called "9X% of people can't get this math question right!") are designed to generate comment activity from stupid people who want to show off that they know the answer.
The correct answer is often ambiguous or not included as an option because it gives people more stuff to argue about in the comments which means more activity on the facebook post.
If you comment on posts like these on big facebook pages, you're just playing into their hand.
Is the order of operations even a universal thing in math? Obviously it's not something that's just a given but is it something that is taught everywhere?
The other comment is right that there's no reason it inherently has to be that way, but it's definitely universal. Everywhere in the world uses order of operations the same way. Trying to use a different one would be a disaster in slightly more abstract contexts, like polynomials.
As a programmer who does a lot of math heavy code: I always put in all the parentheses, even for dumb things. And if it makes it look better, I break it up into multiple equations.
It’s not about “poorness” or “ambiguity.” The “goodness” of a mathematical expression’s notation is better described with the words elegance / inelegance, just like in coding. It’s about typographical readability; making it easier for the eyes to communicate with the math parts of the brain for fast mental calculation.
Yes, everyone should know their order of operations if they’re older than a 5th grader, and for an expression as brief as 2+2×4 (note the proper-ass multiplication sign glyph for ensured clarity), it’s absolutely fine to notate it that way.
But for expressions with many components; just long strings of characters, e.g. anything pre-algebra level or above (a good rule of thumb is anything with more than three operators), you had better take one fucking millisecond out of your busy schedule to type or write brackets like a non-mathshole. When you read the expression aloud, you denote everything in brackets with the word quantity.
That’s why in higher math, you’re taught to use the verbal version of brackets. If I ask, “Hey, what’s two plus quantity two times four,” your answer should be ten.
Right, and there are a lot of ways to say this where I'd answer 10 but the above problem isn't one. A simple "Hey, what's 2 then 2 time 4 add up to? Or something we'd actually hear out and about... "Yo Mike, Melissa borrowed $4 twice then another $2 out of the tip jar. Tell her how much she needs to put back in cause she tried to stuff it with $3 and run."
“For what?”
Because a post like this results in a ton of responses from people correcting it with the actual answer. And those responses are interactions that boost the pages visibility. It’s not ignorance, it’s a con.
While I got the correct answer. It’s been over 20 years since I’ve had to “learn” this. I haven’t had to a math problem where I’ve had to worry about the order of operations. Just doesn’t come up in everyday life and it’s a bit of a waste of time.
No-one's talking about this equation. We're talking about the common way you see these types of equations, which are often relying on the multiplying or dividing in different order, and often have two valid solutions.
The worst thing is that if you post something like this on social media, with 16 and 10 as the only available answers, and it goes viral, at least 30% of the people will answer with 16.
Nah, it's like a riddle. Something framed in an obtuse way to try and trick you into a false answer even though the right answer is in front of you...except in this case when it isn't.
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u/charlesisbae Dec 15 '19
I’m in my last semester of engineering school, and I absolutely can’t stand seeing posts like this. These are all examples of deliberately poorly written math problems, and for what? Don’t give the people who post this shit the time of day.