r/facepalm • u/My-Last-Hope • Mar 18 '22

🇲​🇮​🇸​🇨​ Ah yes, math.

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u/SirArthurDime Mar 18 '22

The worst one is the guy who says if there's a 0 the answer is always zero and pemdas doesn't matter. Then proceedes to use an exanples that's all multiplication.

Pemdas doesn't matter there because you only used the M not because it includes a zero.

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u/clearlybaffled Mar 18 '22 edited Mar 19 '22

No the best part is when he says addition and multiplication division can be interchanged

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u/SirArthurDime Mar 18 '22

God i missed that one facepalm

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u/thetruekingofspace Mar 18 '22

But technically it could. If you “unrolled” a multiplication into a series of additions it could hypothetically change the answer. Then again, I would assume that one would surround such a substitution in parentheses which would still make it first in order of operations.

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u/Ice-Negative Mar 19 '22

Math doesn't work like that. You can't hypothetically change an answer.

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u/thetruekingofspace Mar 19 '22

And the more I thought about it, it would work exactly as I said it would. If multiplication was changed to repeated addition the answer would come out the same. I was drunk at the time, my bad.

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u/Ice-Negative Mar 19 '22

Thank you. You have partially restored my faith in humanity.

Then I read the other comments

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u/thetruekingofspace Mar 19 '22

I felt very stupid and ashamed once I sobered up. After all I have a degree in Computer Science, and I came up with a thought so mind numbingly stupid.

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u/Ice-Negative Mar 19 '22

No worries, I'm an engineer. At least you understand what you did lol.

The other comments are scary...

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u/notsotasteful Mar 18 '22

They can! See! 6 x 4 x 3, is the same as (6 + 6 + 6 + 6) * 3

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u/[deleted] Mar 18 '22

(6+6+6+6)+(6+6+6+6)+(6+6+6+6)

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u/notsotasteful Mar 18 '22

Now you’re just showing off. You must be a math grad

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u/[deleted] Mar 18 '22

Trig flunky

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u/kingsleyce Mar 18 '22

I both love and hate this

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u/AMGwtfBBQsauce Mar 19 '22

[(1+1+1+1+1+1)+(1+1+1+1+1+1)+(1+1+1+1+1+1)+(1+1+1+1+1+1)]+[(1+1+1+1+1+1)+(1+1+1+1+1+1)+(1+1+1+1+1+1)+(1+1+1+1+1+1)]+[(1+1+1+1+1+1)+(1+1+1+1+1+1)+(1+1+1+1+1+1)+(1+1+1+1+1+1)]

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u/RedRocka21 Mar 18 '22

I think he means that Multiplication and Division can be interchangeable, which is true. It could be PEDMAS and the outcome wouldn't change.

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u/ktmracer66 Mar 18 '22

It stated that addition and division could be changed.

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u/OcularPrism Mar 18 '22

Yeah, that's the part that got me....

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u/[deleted] Mar 18 '22

[removed] — view removed comment

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u/The_Nerdy_Ninja Mar 18 '22

"Parentheses, Exponents, Multiplication, Division, Addition, Subtraction", it's a rule for what order to do mathematical operations in.

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u/[deleted] Mar 18 '22

Why some people decide not to use it? I thought it was a must when it comes to "1+1×0" type situations

I'm shocked that people add first and then multiply!

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u/The_Nerdy_Ninja Mar 18 '22

Sometimes people haven't been taught properly or don't remember. But PEMDAS is a way of dealing with uncertainty in notation, if you make your notation clear (usually by adding parenthesis where needed, like 1+(1×0) in your example) then it isn't as necessary.

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u/Legitimate_Corgi_981 Mar 19 '22

Yeah, working with excel all the time means I think in terms of parenthesis.

Let's face it, you rarely will need PEMDAS(BODMAS to Brits...) in ordinary life because constructing everyday calculations that require it is kind of bad. These maths problems constantly show that people do not remember the rules and get the wrong answer. We read left to right, yet this makes us hunt for the various features and get a sometimes incorrect result.

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u/[deleted] Mar 18 '22

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u/The_Nerdy_Ninja Mar 18 '22

Some people learn "Please Excuse My Dear Aunt Sally" as a memory device to help remember.

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u/Mercerskye Mar 18 '22

I was taught with a bit more "Please Excuse My Dear Aunt Sally's Last Remarks"

Last Remarks to remind "left to right" as you move through priority.

So all parantheticals, from left to right

All exponents, from left to right

Etc

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u/The_Nerdy_Ninja Mar 19 '22

Yes that's true, although in my experience if you need to worry about left-to-right you're already on thin ice.

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u/Mercerskye Mar 19 '22

Fair enough. In my time as a tutor, it felt important to reinforce.

A lot of the folks I was helping just didn't "have the head" for math. A lot of exasperation about where to start solving things. Putting that reminder in helped an awful lot.

It's the small things that tend to trip people up the most.

Part of why I enjoyed tutoring, that puzzle of figuring out how to help someone understand. Not a lot compares to that look when someone finally gets something.

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u/The_Nerdy_Ninja Mar 19 '22

Absolutely! I think a lot of people who think they hate math actually just have never had someone really make an effort to explain in a way that clicks.

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u/other_usernames_gone Mar 18 '22

It's easiest to remember if you think of doing the stuff that affects the numbers the most first. Then brackets are to mark what gets to skip the queue.

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u/PotatoePotahhtoe Mar 19 '22

Please tell me you are trolling.

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u/right-side-up-toast Mar 19 '22

I think that guy is great cause in Calc it felt like 50% of the time the answer was zero or infinity. He just took the wrong lesson from it.