48 ÷ 2(9+3)에 관련해서 해외사이트 인용
이제 웬만하면 이거 무시하고 지나갈려고 했는데 다시관련글 올립니다
This next example displays an issue that almost never arises but, when it does, there seems to be no end to the arguing.
• Simplify 16 ÷ 2[8 – 3(4 – 2)] + 1.
• 16 ÷ 2[8 – 3(4 – 2)] + 1
= 16 ÷ 2[8 – 3(2)] + 1
= 16 ÷ 2[8 – 6] + 1
= 16 ÷ 2[2] + 1 (**)
= 16 ÷ 4 + 1
= 4 + 1
= 5
The confusing part in the above calculation is how "16 divided by 2[2] + 1" (in the line marked with the double-star) becomes "16 divided by 4 + 1", instead of "8 times by 2 + 1". That's because, even though multiplication and division are at the same level (so the -to-right rule should apply), parentheses outrank division, so the first 2 goes with the [2], rather than with the "16 divided by". .That is, multiplication that is indicated by placement against parentheses (or brackets, etc) is "stronger" than "regular" multiplication Typesetting the entire problem in a graphing calculator verifies this hierarchy:
Note that different software will process this differently; even different models of Texas Instruments graphing calculators will process this differently. In cases of ambiguity, be very careful of your parentheses, and make your meaning clear. The general consensus among math people is that "multiplication by juxtaposition" (that is, multiplying by just putting things next to each other, rather than using the "×" sign) indicates that the juxtaposed values must be multiplied together before processing other operations. But not all software is programmed this way, and sometimes teachers view things differently. If in doubt, ask!
(And please do not send me an e-mail either asking for or elseproffering a definitive verdict on this issue. As far as I know, there is no such final verdict. And telling me to do this your way will not solve the issue!)
위글에 설명되어있듯이
parenthese outrank devision
괄호가 나누기보다 더 우선이라는겁니다.
That is, multiplication that is indicated by placement against parentheses (or brackets, etc) is "stronger" than "regular" multiplication
즉, 괄호 바로 옆에 있으면서 생기는 곱셈은 일반적인 곱셈보다 더 강하다는 뜻이죠.
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