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New Math (lemmy.ml)
submitted 1 year ago by to c/funny@lemmy.world
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[–] 38 points 1 year ago* (25 children)

Yeah if you put it:

100 - (100 x 0,1) = 90

90 + (90 x 0,1) = 99

It comes quite obvious. And I know the brackets are redundant, but my coder mind forces brackets to all math formulas for readability.

Was it on purpose, maybe.

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  • [–] 18 points 1 year ago (3 children)

    I think of it as

    100 x 0.9 = 90

    90 x 1.1 = 99

    Am I the odd one out?

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  • [–] 15 points 1 year ago (18 children)

    Even

    100 - 10% = 90

    90 + 10% = 99

    Works better than what he did, because that’s how you’d enter it on a standard calculator.

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  • [–] 1 point 1 year ago* (4 children)

    100 - 10/100 ≠ 90

    I'm not a fan of this at all and wish people would treat percentages as if they were a unit. x% is x of y per 100 total.

    x% = x yi / 100 ytotal

    Where yi is the species in question.

    My cup is 90% full: My cup contains 90 unitswater / per 100 unitscup

    This is why I don't like Baker's percentages. I guess it makes sense, because it's still per cent, but they're mixing the meaning used practically everywhere else these days.

    50% water for baking isn't 50 unitswater / per 100 unitsdough, it's 50 unitswater / per 100 units~flour~. In my mind that means you have 33.33% hydration, not 50%...

    Just feels weird to not express that as a ratio. But I guess it's a shorthand that works for them :/

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  • [–] 3 points 1 year ago (3 children)

    Yes I understand all that but I'm telling you standard calculators literally work that way.

    Just launch the calculator app on your phone or computer and give it a try, you'll see.

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  • [–] 4 points 1 year ago (1 child)

    This is very upsetting

    Thanks for the heads-up. I would have been happier never knowing haha

    The implied brackets. THE IMPLIED BRACKETS!! The horror.

    Thanks for the response kind soul

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  • [–] 4 points 1 year ago*

    No worries. Yeah I get that it's a bit weird if you know how to do it properly but it's actually a fairly helpful trick for quickly calculating discounts, which I assume is the indented use. Remember, calculators were designed for lazy business folks who suck at math.

    This is exactly how someone who failed HS math would think about the problem, and conveniently, it just works.

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  • [–] 1 point 1 year ago* (last edited 1 year ago) (12 children)

    Um you can type like that into a calculator? Any answers please specify an actual calculator vs computer.

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  • [–] 2 points 1 year ago (2 children)

    Most of the ones I've used work that way.

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  • [–] 2 points 1 year ago (8 children)

    Sure can.

    And yes I was stunned as well when I learned it, because that's not how it's taught in schools. I used to do exactly what the previous commenter did, and then one day I saw some illiterate mouthbreather type it in like that and I was like "nuh-uh, that's not how that works, gimme that thing and let me show you." And I typed it in the long and "correct" way, and whaddayaknow? Same result.

    But it makes sense when you think about it, calculators were literally invented for business use (and most business people are notoriously bad at math), and one of the most common uses in business is figuring out how much something should cost after applying a discount.

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  • [–] 1 point 1 year ago (7 children)

    Like an actual calculator or one on the computer?

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  • [–] 2 points 1 year ago* (6 children)

    It works on both. I tried the calculator apps on iOS and Windows and they both worked that way. And if you still have a regular old digital calculator, it should work on that too.

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  • [–] 1 point 1 year ago (5 children)

    Nope just tried. 7+10% = 7.1 It converted 10% to be 0.1

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  • [–] 1 point 1 year ago (4 children)

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  • [–] 0 points 1 year ago* (3 children)

    Sigh. Yes on a computer/phone/browser I can see that. On a real life calculator, (which you even referenced as a "regular old digital calculator") I've not see that. That's what I've been talking about from the start JFC.

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  • [–] 2 points 1 year ago (2 children)

    I haven't had one of these in ages but I'm pretty sure that's where I learned the trick.

    Anyways, here are two videos showing it working on different models:

    https://www.youtube.com/shorts/tbQF4NcBA-o

    https://www.youtube.com/shorts/hsdJX0D2178

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  • [–] 0 points 1 year ago* (last edited 1 year ago) (1 child)

    If it has a double zero it's probably an accounting calculator.

    But in any case, in case you didn't notice when I said JFC that means I'm not interested in talking with someone that intentionally misreads what's said and posts a picture of a fucking iPhone calculator JFC. Ciao.

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