Author Topic: Singaporean children's maths problem  (Read 3535 times)

Wowbagger

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Singaporean children's maths problem
« on: 13 April, 2015, 01:29:17 pm »
http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/13/can-you-solve-the-singapore-primary-maths-question-that-went-viral

My immediate reaction is that I cannot see how telling one pal the day number, and the other the month, of her birthday enables either of them to work out the precise date, or how the information that each subsequently gives helps the other to work it out.
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Biggsy

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Re: Singaporean children's maths problem
« Reply #1 on: 13 April, 2015, 03:27:47 pm »
Brain not in gear, so I had to look at the comments, and find a comment that I could understand and follow.

I think it's
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Kim

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Re: Singaporean children's maths problem
« Reply #2 on: 13 April, 2015, 03:51:50 pm »
Hmm, let's see:

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To me that's a *hard* 12+ question, not year 5.  But Singaporean children may be better at logic problems simply through merit of not being western, or else year 5 means something different there.  It certainly means something different here to what it did when I was in year 5.

Biggsy

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Re: Singaporean children's maths problem
« Reply #3 on: 13 April, 2015, 04:22:04 pm »
Guardian update: "It now appears that the question was not intended for year 5 primary schoolkids but in fact for 14/15-year olds."

Still hard for a 15 yo, I think.
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Mr Larrington

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Re: Singaporean children's maths problem
« Reply #4 on: 13 April, 2015, 05:01:09 pm »
Hard for a 51 year old too...
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red marley

Re: Singaporean children's maths problem
« Reply #5 on: 13 April, 2015, 05:10:15 pm »
Hmm, let's see:

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I have a different answer, and am probably wrong...

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Kim

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Re: Singaporean children's maths problem
« Reply #6 on: 13 April, 2015, 05:17:25 pm »
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Wowbagger

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Re: Singaporean children's maths problem
« Reply #7 on: 13 April, 2015, 05:22:51 pm »
I saw the logic eventually but confess to reading the BTL comments for the solution.

I think it helps to write the months and dates in tabular form and solve it visually, thusly:

14th15th16th17th18th19th
May***
June**
July**
August***

That way, you can see at a glance that 18th & 19th are sticking out like sore thumbs.
Quote from: Dez
It doesn’t matter where you start. Just start.

red marley

Re: Singaporean children's maths problem
« Reply #8 on: 13 April, 2015, 06:27:24 pm »
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I must be being dense here, but I still don't get...

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red marley

Re: Singaporean children's maths problem
« Reply #9 on: 13 April, 2015, 08:22:55 pm »
Ahh. Just worked out why Kim's reasoning can work...

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(Edit: Or basically what Owen61 says in Biggsy's post)

Re: Singaporean children's maths problem
« Reply #10 on: 13 April, 2015, 08:59:12 pm »
I saw the logic eventually but confess to reading the BTL comments for the solution.

I think it helps to write the months and dates in tabular form and solve it visually, thusly:

14th15th16th17th18th19th
May***
June**
July**
August***

That way, you can see at a glance that 18th & 19th are sticking out like sore thumbs.
That's exactly how I did it, and got to the right answer.
Rust never sleeps

Re: Singaporean children's maths problem
« Reply #11 on: 14 April, 2015, 04:21:56 pm »
I see the BTL geniuses in the Guardian are still trying to argue that Alex Bellos's (and Kim's) solution is wrong  ;D
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Wowbagger

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Re: Singaporean children's maths problem
« Reply #12 on: 17 April, 2015, 08:39:51 am »
The Toady prog has come out with a similar maths/logic problem.

http://www.bbc.co.uk/programmes/p02pc26p

I'm struggling to see why, in their solution, the three "key" possibilities are given if there are seven possible permitations with three prisoners wearing any of 5 hats of two different colours.
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Re: Singaporean children's maths problem
« Reply #13 on: 17 April, 2015, 08:41:53 am »
I heard that too. I think I detected a flaw in the logic, but I haven't sat down and worked it out properly yet.
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Re: Singaporean children's maths problem
« Reply #14 on: 17 April, 2015, 11:09:31 am »
Goes like this

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“There is no point in using the word 'impossible' to describe something that has clearly happened.”
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rr

Re: Singaporean children's maths problem
« Reply #15 on: 17 April, 2015, 12:48:09 pm »
Missed this thread, I solved in about 10 minutes after drawing a Wow style table.
Mini, who has just turned 14 and got a gold award in the junior math challenge last year, solved it in under 5 minutes without writing anything down.

Wowbagger

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Re: Singaporean children's maths problem
« Reply #16 on: 18 April, 2015, 12:55:44 pm »
A Smarrtarrse?  :P
Quote from: Dez
It doesn’t matter where you start. Just start.