越南小學(xué)數(shù)學(xué)題難倒一片人

Forget Singapore.
別提新加坡了。

The latest brain-mangling maths puzzle to hit the news is from Vietnam.
最近登上新聞?lì)^條的燒腦數(shù)學(xué)題來(lái)自越南。

It’s posted above. You need to fill in the gaps with the digits from 1 to 9 so that the equation makes sense, following the order of operations - multiply first, then division, addition and subtraction last.
如上圖所示。你需要用1到9的數(shù)字將所有空格填滿，并且使等式成立，計(jì)算的順序?yàn)椋瘸耍又缓笫羌樱詈笫菧p。

According to the VN Express, it was set as a problem for third graders in the town of Bao Loc in the Vietnamese highlands.
據(jù)報(bào)道，這道題目是越南保祿地區(qū)小學(xué)三年級(jí)的數(shù)學(xué)題。

That’s eight year olds!
他們可只有8歲啊！

There is no complicated maths involved, only basic arithmetic. But it’s not a walk in the park.
這題目沒(méi)有涉及任何復(fù)雜的運(yùn)算，只有基本的算術(shù)。但做起來(lái)一點(diǎn)也不容易。

“This problem is difficult even for adults good at math, so it will be difficult for students in grades 3, and even more challenging for students in the highlands,” teacher Tran Phuong told VN Express.
一位老師說(shuō)：“就算對(duì)數(shù)學(xué)很好的成年人來(lái)說(shuō)，這道題也很難解。所以對(duì)三年級(jí)的學(xué)生來(lái)說(shuō)肯定很難，對(duì)高地地區(qū)的學(xué)生就更難了。”

He added: “I sent the problem for some people, including a doctorate in economics with mathematics, but they have not given the answer.”
他還說(shuō)：“我把這道題發(fā)給了一些人，其中包括一位有數(shù)學(xué)背景的經(jīng)濟(jì)學(xué)博士，但他們都還沒(méi)有給出答案。”

Vietnam does very well in the international PISA tables that compare 15-year-olds’ performance in maths, science and reading. Vietnam ranks 17 in maths and 8 in science, which outperforms many Western countries like the UK (26 and 20) and US (36 and 28).
越南的學(xué)生在國(guó)際學(xué)生評(píng)估項(xiàng)目的數(shù)學(xué)、科學(xué)和閱讀領(lǐng)域表現(xiàn)都不俗。他們?cè)跀?shù)學(xué)領(lǐng)域排名17，在科學(xué)領(lǐng)域排名第8，比英國(guó)（這兩項(xiàng)分別排名26和20）和美國(guó)（分別排名36和28）都出色。

No wonder if they are given problems like this....
難怪他們能出這樣的題目......

Can you do it?
你能解出這道題嗎？

Here is one of the solutions from a commenter at Gizmodo: There are other possible solutions, but the first one I came up with was: 6, 9, 3, 5, 2, 1, 7, 8, 4 in that order ... How I got to it was assigning each blank to a letter and writing the whole thing as an equation then grouping like terms.
以下是Gizmodo網(wǎng)站一位網(wǎng)友給出的答案：可能還有別的解法，但我最先想到的是：空格中依次填6, 9, 3, 5, 2, 1, 7, 8, 4。我用字母代替每一個(gè)空格，然后把整個(gè)等式列出來(lái)，再進(jìn)行同類(lèi)項(xiàng)合并。

So... a+13(b/c)+d+12e-f+(gh/i)-21=66.
算式是這樣的：a+13(b/c)+d+12e-f+(gh/i)-21=66。

Then you add 21 to both sides and a+d-f+13(b/c)+12e+(gh/i)=87. And since you’re limited to plugging in numbers between 1-9 for a-i, you see that there’s only so many combinations that will yield numbers close to 87. So then you start guessing and checking how large you have to make the various numbers to make it work. You need smaller numbers in the denominators and the subtraction and larger numbers being multiplied.
給算式兩邊都加21，就得出a+d-f+13(b/c)+12e+(gh/i)=87。字母a到i的空格中只能填入1到9 的數(shù)字，計(jì)算結(jié)果能得出87的變化組合也就那么多。所以你就可以邊猜邊調(diào)整，最后得出正好的結(jié)果。分母和減號(hào)后面的數(shù)字要小一些，乘號(hào)后面的數(shù)字要大一些。

Vocabulary:
brain-mangling: 費(fèi)腦筋的，燒腦的
walk in the park: 很容易的事
like terms: 同類(lèi)項(xiàng)
denominator: 分母

（中國(guó)日?qǐng)?bào)網(wǎng)英語(yǔ)點(diǎn)津 馬文英）