• TC_209 [he/him, comrade/them]@hexbear.netEnglish
      9·
      8 days ago

      It’s a math joke (“”“joke”“”) about misunderstanding the intent behind written problems, as poorly-written problems can be interpreted in multiple ways, but well-written problems are (almost) always correctly interpreted by reasonably math literate folks. The fact the you arrived at two different solutions means that you correctly interpreted the intent behind both problems.

        • Hex [he/him]@hexbear.netEnglish
          2·
          7 days ago

          I’m not trying to start an argument over this, but I respectfully disagree.

          6 / 2 * (1 + 2)

          6 / 2 * 3

          3 * 3

          9 edit: accidentally said 6 here

          Parentheses first, then division and multiplication granting priority to operations on the left.

          • The_sleepy_woke_dialectic [he/him]@hexbear.netEnglish
            2·
            7 days ago

            If it’s 2(1 + 2) that’s considered one “term” and heavily implies that you should FOIL first before anything else. It isn’t the same as 2 * (2 + 1). Of course you wouldn’t likely get an equation like that without knowing “what” you’re doing, which would answer any ambiguity.

            • Imnecomrade [none/use name]@hexbear.netEnglish
              2·
              7 days ago

              2(1 + 2) does imply multiplication: 2 * (1 + 2). The reason it counts as one term, as I noted below, is because it is inside a two-dimensional fraction which has implicit parathenses in the numerator, denominator, and the fraction itself. The first equation is actually ((6) / (2(1 + 2))). When a fraction is written in two dimensions instead of a single string, the division between the numerator and the denominator is supposed to be done last.

              The first equation is not 6 / 2(1 + 2). If it was, this means you get (6 / 2) * (1 + 2) as in the second equation, which means (1 + 2) is moved up to the numerator ((6(1+2)) / 2 = (6 / 2) * (1 + 2)), which means the two problems are not equal to each other. I believe this is the point of the “joke”.

              • The_sleepy_woke_dialectic [he/him]@hexbear.netEnglish
                1·
                7 days ago

                If I wrote 6 ÷ 2x, x=3 you wouldn’t try to divide by just the 2. The 2 is “part of” the term (2x) which is how the majority of cases where you would actually see something like 2(some number) would work. PEMDAS BODMAS or whatever other mnemonic be damned

                (I’m not arguing this passionately in any way I just like arguing <3)

                • Imnecomrade [none/use name]@hexbear.netEnglish
                  1·
                  7 days ago

                  2x still means 2 * x.

                  https://www.wolframalpha.com/input?i=6%2F2x

                  x is still multiplied last. There’s not a rule for implied multiplication shorthand preceding operations to the left. You still need to wrap 2x in parentheses if you want the operation to occur first.

                  https://www.wolframalpha.com/input?i=6%2F(2x)

                  This isn’t like a polynomial like ax^2 + bx + c as division is done between 6 and 2 before multiplication with x. Typically you wouldn’t see such an equation (which is intended to trick you) as normally addition or subtraction would occur like in a polynomial or another variable equation (such as a linear graph), which would be done after the exponents, multiplication, and division with the variables are calculated. In the instance you wrote, it should be written as (6/2)x, or 3x, to avoid obscuring the equation. Though you intended for 6/(2x), or 3/x.

                  And no worries, comrade, I’m just meaning to help since I am good at math and like helping people (I don’t mean this in an egotistical way). I’m not taking offense, and I am not meaning to offend anyone.

          • Imnecomrade [none/use name]@hexbear.netEnglish
            1·
            7 days ago

            Assuming the first way is written correctly, the equation is actually 6 / (2 * (1 + 2)). The (1 + 2) is still inside the denominator. So it is solved as follows:

            6 / (2 * (1 + 2))

            6 / (2 * 3)

            6 / 6

            1

            The second equation incorrectly takes out the (1 + 2) and places it as the numerator on the side. In order to take that piece out correctly, it would have to be: (6 / 2) * (1 / (1 + 2))

            And to solve it, it would look like as follows:

            (6 / 2) * (1 / (1 + 2))

            3 * (1 / (1 + 2))

            3 * (1 / 3)

            3 / 3

            1

            Also, 3 * 3 = 9 in regards to second incorrect equation (incorrect meaning the second incorrectly refactored equation from the pic that you answered correctly up until the last operation).

            I think The_sleepy_woke_dialectic forgot to put parentheses around the denominator, but I believe it was meant to be interpreted as the entire denominator as shown in the pic.

            • Hex [he/him]@hexbear.netEnglish
              1·
              7 days ago

              My bad on typing 6 as the final number, typo.

              I think the image is discussing the two ways most people interpret the (deliberately slightly obtuse) equation 6 / 2(1+2) Following BEDMAS BOMDAS PEMDAS or however you call it in your area as written, the correct interpretation is interpretation #2, which resolves to 9,

              However many people also interpret the implitic multiplication in 2(1+2) to have higher priority, or makes the 2 and () into one unit, as if put into Parentheses, which leads to interpretation #1, which resolves to 1.

              The real answer is to make the original question less obtuse, but any parsing algorithm correctly given the rules of mathematical notation would resolve it to 9