• DefederateLemmyMl@feddit.nl
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    2 days ago

    If you have a bunch of unparenthesized addition and subtraction, left to right is correct

    If you have a bunch of unparenthesized addition and subtraction, left to right doesn’t matter.

    1 + 2 + 3 = 3 + 2 + 1

    • KubeRoot@discuss.tchncs.de
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      1 day ago

      If you have a bunch of unparenthesized addition and subtraction, left to right doesn’t matter.

      Right, because 1-2-3=3-2-1.

        • KubeRoot@discuss.tchncs.de
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          6 hours ago

          I did not flip any signs, merely reversed the order in which the operations are written out. If you read the right side from right to left, it has the same meaning as the left side from left to right.

          Hell, the convention that the sign is on the left is also just a convention, as is the idea that the smallest digit is on the right (which should be a familiar issue to programmers, if you look up big endian vs little endian)

    • MotoAsh@piefed.social
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      2 days ago

      True, but as with many things, something has to be the rule for processing it. For many teachers as I’ve heard, order of appearance is ‘the rule’ when commutative properties apply. … at least until algebra demands simplification, but that’s a different topic.

        • MotoAsh@piefed.social
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          2 days ago

          No, you completely misunderstood my point. My point is not to describe all valid interpretations of the commutative property, but the one most slow kids will hear.

          OFC the actual rule is the order doesn’t matter, but kids that don’t pick up on the nuance of the commutative property will still remember, “order of appearance is fine”.

        • Quatlicopatlix@feddit.org
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          2 days ago

          Yes thank you! If you have a sum it is really great to order it in a way that makes it better to ad in your head and i think that lots of people do that without thinking about it. X=2+3+1+6+2+4+7+5 X=2+3+5+4+6+7+1+2 X=5+5 + 10 +7+1+2 X=10 + 10 + 7+3 X=10 + 10 + 10