6 年级数学题

Xiangdang · 发表于 2009-3-24 07:50:08

Can you find the number of ordered positive integers (x,y) so that

1/x + 1/y = 1/2007

Good luck.

buxiang · 发表于 2009-3-24 08:13:57

For example, (3600, 10800), (2800, 75600), ... .

Xiangdang · 发表于 2009-3-24 16:47:41

Yes, find all the pairs (x,y)'s.

...... · 发表于 2009-3-25 03:19:39

好长的焦距.

学生 · 发表于 2009-3-25 04:29:23

看错了吧。题中是２００７，不是２７００。

学生 · 发表于 2009-3-25 04:42:09

Three solutions: (2008, 4030056), (2016, 449568), (2088, 51736).

Xiangdang · 发表于 2009-3-25 06:28:38

You only found three of the multiple possible solutions. The problem asks you to find them all or just say how many pairs of positive integers(x,y) can be the solution. Just give me a number, that's it.

idiot94 · 发表于 2009-3-25 08:52:57

I do not know... since it is for 6 grades, let me take a wild guess then, is it 6+1=7?

HF: · 发表于 2009-3-25 19:30:07

8 -- if the 6th grader knows a little bit programming.

Xiangdang · 发表于 2009-3-27 02:16:42

It was a 6 grader math contest problem in the US. Who said US kids don't know math!

山里来的孩子 · 发表于 2009-4-3 16:30:49

I got 27 on a spreadsheet format. But it does not cover all just yet.

I have to admit that I have no clue on some of contest questions my son brought home from his school. US schools are more like a free world too. You can take very hard courses, you can also just kill your time there by doing almost nothing. If we compare average scores, yes you can say the kids here are not as good as in China in terms of math, sciences, etc.. But if you compare top students, you will be surprised.

只看该作者 · 发表于 2009-5-26 06:51:36

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周心宇 · 发表于 2009-8-4 21:33:40

发答案太琐碎，稿子在岸书桌上。

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6 年级数学题

Solutions are not unique

Read the problem!

回复：6 年级数学题

看错了吧

回复：6 年级数学题

More, more

it seems too hard for a 6 grade problem...

回复：More, more

回复：it seems too hard for a 6 grade problem...

回复：there are definitely more than 8 pairs...

共14组自然数可满足条件。