Kids homework. I&#...
 

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[Closed] Kids homework. I'm thick!

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 benz
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Order the digits 1, 2, 3, 4 to make a number which is divisible by 4.

When the final digit is removed it becomes a 3 digit number which is divisible by 3.

And when the final digit is removed again it becomes a 2 digit number which is divisible by 2.

Then finally a 1 digit number which is divisible by 1.

Help!


 
Posted : 10/11/2017 9:23 pm
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oops


 
Posted : 10/11/2017 9:28 pm
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4312

No, hang on I’ve removed the wrong numbers


 
Posted : 10/11/2017 9:34 pm
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1234


 
Posted : 10/11/2017 9:35 pm
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Nope


 
Posted : 10/11/2017 9:37 pm
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assuming solutions in whole numbers something's off here


 
Posted : 10/11/2017 9:38 pm
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.


 
Posted : 10/11/2017 9:39 pm
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Trick question - any combo will work, it doesn't say the answer can't be a decimal.


 
Posted : 10/11/2017 9:41 pm
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As above.


 
Posted : 10/11/2017 9:45 pm
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I can't find an answer where the division yields a whole number.


 
Posted : 10/11/2017 9:45 pm
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4444 works, but isn't in the rules as I read them.


 
Posted : 10/11/2017 9:46 pm
 km79
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A number is divisible by 4 if the last two digits are a number that is divisible by 4


 
Posted : 10/11/2017 9:49 pm
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Is what you've written EXACTLY how the puzzle is written?

Could it be asking for a number where the number formed by combining (sum of) all 4 must be divisible by 4, the number formed by the sum of the first 3 is divisible by 3, and so on?

EDIT No because 10/4 isn't whole. I've seen this before but with more numbers and that's how it worked.


 
Posted : 10/11/2017 9:50 pm
 km79
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https://nrich.maths.org/7218 here is the same question.


 
Posted : 10/11/2017 9:52 pm
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As I see it, the following are the only sequences which could be considered potential matches, and none of them meet the criteria.

1 2 3 4
3 2 1 4
1 4 3 2
3 4 1 2


 
Posted : 10/11/2017 9:54 pm
 benz
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The question is as worded, but starts...

Can you....

No!


 
Posted : 10/11/2017 9:54 pm
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As allthepies said, can't be done to produce whole numbers
(IMO)

if the 4 digit number has to be divisible by 4 then the last digit has to be 2 or 4

since the 2 digit number has to be divisible by 2 then the second digit has to be 4 or 2

once you have that there are very few possibilities and none of them works


 
Posted : 10/11/2017 9:54 pm
 benz
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Yes, straight from the website linked to, but the homework sheet is missing the last paragraph.

Keep em comin....


 
Posted : 10/11/2017 9:57 pm
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Just say it can't and explain why (nicking allthepies succinct explanation to do so). Top marks will surely follow.


 
Posted : 10/11/2017 9:59 pm
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is this really about the divisibility by... rules:
anything is divisible by 1
even numbers by 2
if the sum of the digits divides by three then the number will too (1+2+3 = 6 ... 123/3= 41 , etc)
if the last two digits divide by 4 (per all the pies)
etc

so if the question is can you? No I can't and here's why...


 
Posted : 10/11/2017 10:00 pm
 km79
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Unfortunatly the solution page https://nrich.maths.org/7218/solution must require a subscribtion or log on or something as it just shows the same as the problem page for me.

EDIT: Try this https://nrich.maths.org/7218&part=note

It is not possible to find a four-digit or a five-digit number that follow these rules but you can expect the children to be able to convince you this is the case.
FFS what age group is Stage 2?


 
Posted : 10/11/2017 10:04 pm
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Teacher copied from> https://nrich.maths.org/7218 ?

But didn't check to see if there is actually a valid solution ?

Woffle words on "possible approach" https://nrich.maths.org/7218/note


 
Posted : 10/11/2017 10:04 pm
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Ah, and the woffle leads trhrough to proof that it can't be done (as we'd already shown, go us!)
[url= https://nrich.maths.org/796/solution ]american billions solution[/url]


 
Posted : 10/11/2017 10:09 pm

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