• aliceblossom@lemmy.world
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      7 months ago

      Because its not really “1 plus 3”, its negative 1 plus 3 which is two. I know it seems a little weird but the minus sign is " tied" to the thing following it.

    • cecilkorik@lemmy.ca
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      7 months ago

      Parenthesis, exponents, multiplication, division, addition, subtraction.

      should actually be

      Parenthesis, exponents, (multiplication and division), (addition and subtraction).

      Addition and subtraction are given the same priority, and are done in the same step, from left to right.

      It’s not a great system of notation, it could be made far clearer (and parenthesis allow you to make it as clear as you like), but it’s essentially the universal standard now and it’s what we’re stuck with.

      • iglou@programming.dev
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        7 months ago

        No, it should simply be “Parenthesis, exponents, multiplication, addition.”

        A division is defined as a multiplication, and a substraction is defined as an addition.

        I am so confused everytime I see people arguing about this, as this is basic real number arithmetics that every kid in my country learns at 12 yo, when moving on from the simplified version you learn in elementary school.

        • 13igTyme@lemmy.world
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          7 months ago

          You want PEMA with knowledge of what is defined, when people can’t even understand PEMDAS. You wish for too much.

          • iglou@programming.dev
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            7 months ago

            I’m just confused as to how that is not common knowledge. The country I speak of is France, and we’re not exactly known for our excellent maths education.

          • iglou@programming.dev
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            6 months ago

            Yes, it is. The division of a by b in the set of real numbers and the set of rational numbers (which are, de facto, the default sets used in most professions) is defined as the multiplication of a by the multiplicative inverse of b. Alternative definitions are also based on a multiplication.

            That’s why divisions are called an auxilliary operation.

            • Yes, it is

              No it isn’t.

              The division of a by b in the set of real numbers and the set of rational numbers (which are, de facto, the default sets used in most professions) is defined as the multiplication of a by the multiplicative inverse of b

              No it isn’t. The Quotient is defined as the number obtained when you divide the Dividend by the Divisor. Here it is straight out of Euler…

              Alternative definitions are also based on a multiplication

              Emphasis on “alternative”, not actual.

              • iglou@programming.dev
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                6 months ago

                No it isn’t.

                Yes, it is.

                No it isn’t. The Quotient is defined as the number obtained when you divide the Dividend by the Divisor. Here it is straight out of Euler…

                I’m defining the division operation, not the quotient. Yes, the quotient is obtained by dividing… Now define dividing.

                Emphasis on “alternative”, not actual.

                The actual is the one I gave. I did not give the alternative definitions. That’s why I said they are also defined based on a multiplication, implying the non-alternative one (understand, the actual one) was the one I gave.

                Feel free to send your entire Euler document rather than screenshotting the one part you thought makes you right.

                Note, by the way, that Euler isn’t the only mathematician who contributed to the modern definitions in algebra and arithmetics.

                • I’m defining the division operation, not the quotient

                  Yep, the quotient is the result of Division. It’s right there in the definition in Euler. Dividend / Divisor = Quotient <= no reference to multiplication anywhere

                  Yes, the quotient is obtained by dividing… Now define dividing.

                  You not able to read the direct quote from Euler defining Division? Doesn’t mention Multiplication at all.

                  The actual is the one I gave

                  No, you gave an alternative (and also you gave no citation for it anyway - just something you made up by the look of it). The actual definition is in Euler.

                  That’s why I said they are also defined based on a multiplication

                  Again, emphasis on “alternative”, not actual.

                  implying the non-alternative one (understand, the actual one) was the one I gave

                  The one you gave bears no resemblance at all to what is in Euler, nor was given with a citation.

                  Feel free to send your entire Euler document rather than screenshotting the one part

                  The name of the PDF is in the top-left. Not too observant I see

                  you thought makes you right

                  That’s the one and only actual definition of Division. Not sure what you think is in the rest of the book, but he doesn’t spend the whole time talking about Division, but feel free to go ahead and download the whole thing and read it from cover to cover to be sure! 😂

                  Note, by the way, that Euler isn’t the only mathematician who contributed to the modern definitions in algebra and arithmetics.

                  And none of the definitions you have given have come from a Mathematician. Saying “most professions”, and the lack of a citation, was a dead giveaway! 😂

    • fluxion@lemmy.world
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      7 months ago

      Addition/subtraction work out the same regardless of how you order the operations. If you do subtraction last you start with the original:

      9-1+3

      and you are adding 3 to the result of (9-1). Since you are trying to perform it before the (9-1) operation is carried out, you can add 3 to the 9:

      12-1 = 11

      or you can add three to the -1 and get:

      9+2 = 11

      You only end up with 9-4 if you were subtracting 3 rather than adding three. It all becomes more obvious if you read the original as:

      9 + (-1) + 3

    • Geodad@lemm.ee
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      7 months ago

      It’s multiplication or division from left to right followed by addition or subtraction, also from left to right.

      That’s where a lot of people fuck up.