6÷2(1+2)=多少

[ForwardRetreat]

RT.

 

[solitaire]

=1

 

[大金刚]

9?

 

[ccc]

这题，前些时候这里贴过。

 

[carmen0612]

0....

 

[salas88]

我认为可以等于除１以外的任何数，当然我也不排除它等于１的可能

 

[solitaire]

换种写法吧，更明显些

6/2(1+2)=1

 

[hcloud]

出题错误吧。 故意把可以很明确的东西写的有可能发生歧义， 这就是trick question啊。

(更正）
http://www.purplemath.com/modules/orderops2.htm

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 left-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:

calculator screen-shot: 16 / 2(8) = 1, but 16 / 2 * 8 = 64

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 else proffering 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!)


出这道题是考运算顺序而已……

 

[viper99]

要是我做，答案是1了
好像是我们台湾同胞的小学生考题，多数成人都答错了

 

[shemozhuben]

括号最优先，乘除从左往右，答案：9

 

[老华侨]

括号最优先，乘除从左往右，答案：9

对。
说得确切点，就是两个原则：

• 一个是PEMDAS原则，即："Parentheses -> Exponents -> Multiplication|Division -> Addition|Subtraction" 原则。其中“|”两边是同级的。
• 另一个是同级的遵从从左到右原则。

所以答案是：
6÷2(1+2)
=6÷2*3
=3*3
=9

如果写成 6÷2*(1+2)=? 就更清楚了。

 

[hunksalim]

9,小学生题目

 

[CFC_QUEST]

括号最优先，乘除从左往右，答案：9

就你这水平还搞投资? 先歇着吧!

 

[GRAND KING]

9是正确答案。

 

[明天MT]

出题错误吧。 故意把可以很明确的东西写的有可能发生歧义， 这就是trick question啊。

(更正）
http://www.purplemath.com/modules/orderops2.htm

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 left-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:

calculator screen-shot: 16 / 2(8) = 1, but 16 / 2 * 8 = 64

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 else proffering 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!)


出这道题是考运算顺序而已……

16 ÷ 2[8 – 3(4 – 2)] + 1 = 17