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Math stuff: 11x11= 121 and 1111x1111 = 1234321 and 111111x111111 = 12345654321

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Bucky Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 03:59 PM
Original message
Math stuff: 11x11= 121 and 1111x1111 = 1234321 and 111111x111111 = 12345654321
See the pattern?

1,111,111 x 1,111,111 = 1,234,567,654,321

11,111,111 x 11,111,111 = 123,456,787,654,321

111,111,111 x 111,111,111 = 12,345,678,987,654,321

so what happens next? My Excel program says that...

1,111,111,111 x 1,111,111,111 = 1,234,567,900,987,650,000

But that doesn't look right to me.

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Dr. Strange Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 04:04 PM
Response to Original message
1. Damn that base ten!
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pokerfan Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 04:22 PM
Response to Original message
2. Reminds me of my favorite on-line puzzle
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rug Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 04:27 PM
Response to Original message
3. Why are there 13 in a baker's dozen?
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Bucky Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 04:41 PM
Response to Reply #3
4. "and one to grow on" - Just another way to create customer goodwill
Sadly, when I go to the donut shop, they only give me 12.
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foo_bar Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 05:22 PM
Response to Original message
5. I guess it stops being cool after 9 digits in base 10
in base 11: 1,111,111,111 x 1,111,111,111 = 123456789A987654321
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Strong Atheist Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 05:23 PM
Response to Original message
6. Rounding, since it would HAVE to end in a "1". nt.
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foo_bar Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 05:24 PM
Response to Reply #6
7. that too.
Edited on Wed Aug-19-09 05:29 PM by foo_bar
Imprecision to be precise:

We sometimes get mails from our customers claiming to have found a calculation error in Excel, when in fact the calculation isn't wrong, but the side effects of binary floating point precision make it seem that way. <...>

The resulting value in A3 is 1.2E+100, the same value as A1. This is because Excel stores 15 digits of precision. At least 100 digits of precision would be required to calculate the formula above.

http://blogs.msdn.com/excel/archive/2008/04/10/understa...

So Microsoft says it isn't the wrong answer, you just need to lower your expectations.
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Strong Atheist Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Aug-19-09 05:30 PM
Response to Reply #7
8. "it isn't the wrong answer, it just isn't right." - That's just
wrong...


:rofl:


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