What makes non-PEMDAS answers invalid?
It seems to me that even the non-PEMDAS answer to an equation is logical since it fits together either way. If someone could show a non-PEMDAS answer being mathematically invalid then I’d appreciate it.
My teachers never really explained why, they just told us “This is how you do it” and never elaborated.
In: 834
For the same reason we require you to treat a + as “addition”.
Yes, the equation would still *look* fine and logical if you decided that a + now means “multiplicaiton” and that `*` means “subtraction”. You could also decide that the symbol “17” now means “two hundred and forty point three”. It would be mathematically valid, it just wouldn’t mean whatever the author *wanted* it to mean.
If I write `2 + 3 * 7`, my intent is for you to read it as “two plus the result of multiplying three by seven”. If we follow the same mathematical rules then you will be able to read it the way I intended it.
These conventions are communication tools. They allow us to write things down and have other people read them *and gain the same understanding*. If you don’t follow the same conventions as everyone else then you won’t understand what they meant by what they wrote, and they won’t understand what you mean with what you write. Then you’re no longer speaking the same language.
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