Which of these doesn't belong with the others?

• 64251100571
• 526150732962
• 273814610721
• 947135861977
• 63172924599

Yes, this IS SOLVABLE!

The first thing I notice is that the second one is even, the others are odd.  That's probably not what you were getting at, which is why you should state an assumption or two.  This is an irritating way to pose a math question. 

As folderol says one is even, the others are odd. Apart from that, none is prime and beyond that I haven't a clue what i am looking for.

 folderol got it.

Lesson?  Look for the simplest explanation first.  Sometimes we tend to assume that the answer is complex. 

(evil laugh)

 Charlie91, if you want complex, figure out why each LAST digit is what it is!

(THIS CHALLENGE CAN BE SOLVED BY ANYONE)

I thought folderol got it already--there's more explanation?  You asked why so it might be a series?  Any more clues?

Charlie91 wrote: I thought folderol got it already--there's more explanation?  You asked why so it might be a series?  Any more clues?

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What is the method to figuring each last digit?

xbigboy wrote: Charlie91 wrote: I thought folderol got it already--there's more explanation?  You asked why so it might be a series?  Any more clues?

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What is the method to figuring each last digit?

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 The 1st,3rd,4th,and 5th numbers all have odds. (1,1,7,9) Only the second one is even, so the second one doesn't belong in the group.

Davidmingming wrote: xbigboy wrote: Charlie91 wrote: I thought folderol got it already--there's more explanation?  You asked why so it might be a series?  Any more clues?

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What is the method to figuring each last digit?

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 The 1st,3rd,4th,and 5th numbers all have odds. (1,1,7,9) Only the second one is even, so the second one doesn't belong in the group.

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folderol said that.

WHY IS THE SECOND ONE EVEN?

BECAUSE IT ENDS WITH A 2!!!!!!

Another thing I noticed the first and fifth one have eleven digits. The second to forth have 12 digits.

More precisely the second one can be expressed as 2n, where n is a natural number. 

folderol wrote: More precisely the second one can be expressed as 2n, where n is a natural number. 

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What?

That is a definition of an even number.  An odd number would be 2n + 1 where n is a natural number.  A natural number is also known as a counting number 1, 2, 3, 4, etc, (sometimes includes zero depending on the book).

Substitute any natural number in the expression 2n and you will get an even number.  Likewise, sustitute any natural number in the expression 2n + 1 and you will get an odd number.   

 

 

can some one please tell me what this has to do with Chess