• DarkMessiah@lemmy.world
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    8 months ago

    Actively wrong.

    PE(MD)(AS).

    Parenthesis comes first, do everything in each of them as though they were a whole equation to themselves.

    8/2(2+2) = 8/2(4)

    Then you do your exponents. The equation doesn’t have any, so we can go ahead and skip those.

    Multiplication and division are the same operation, just flipped around, so you go left to right and do those as you come across them. A number next to a parenthesis means multiplication, so to simplify:

    8/2(4) = 8/2x4

    8/2x4 = 4x4

    4x4 = 16

    Addition and subtraction don’t have any weird effects on the outcomes of each other, so you go left to right and do them as they come up. This equation has no more addition or subtraction to do, so we can consider what we have left our answer.

    Therefore: 8/2(2+2)=16

    This is straight from the textbook. You are wrong, and so are your purpose-built calculators.

    EDIT: Replaced * with x to avoid italicising.

    • Zagorath@aussie.zone
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      8 months ago

      Replaced * with x to avoid italicising.

      You can do this without needing to replace by using a backslash. 1*2 comes from 1\*2.

      Anyway, the problem with your logic is that it’s using rules designed for primary school by one random primary school teacher many decades ago. Not a rigorous mathematical convention.

      In real maths, mathematicians frequently use juxtaposition to indicate multiplication at a higher priority than division. Rather than BIDMAS, something like BIJMDAS might work. But that isn’t as catchy, and more to the point: it requires understanding of an operation that doesn’t get used in primary school, so would be silly to put in to a mnemonic designed to aid probably school children.

      • DarkMessiah@lemmy.world
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        8 months ago

        Just looked it up. Everything I know is a lie. Thank you, kind stranger on the internet. I’m going to go have an existential crisis, now.