Excel + Calculations


by StevieTNZ
Tags: calculations, excel
StevieTNZ
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#1
Oct22-13, 12:45 PM
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Hi there,

If I perform the following calculation in Excel:
=100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000,000+50

I get: 100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 ,000,000,000,000,000,000,000,000

Shouldn't the answer be:
100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 ,000,000,000,000,000,000,000,050?
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phinds
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#2
Oct22-13, 02:41 PM
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No, the answer will be constrained by the number of bits used by the computer to represent the numbers, and you've got WAY more than it can handle, so the 50 gets dropped as a rounding error.
jtbell
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#3
Oct22-13, 02:59 PM
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According to

http://en.wikipedia.org/wiki/Numeric...icrosoft_Excel

numbers in Excel are limited to 15 significant figures. So 100,000,000,000,000+50 works, but 100,000,000,000,000,000+50 doesn't.

StevieTNZ
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#4
Oct22-13, 03:55 PM
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Excel + Calculations


Is there any other program out there that will present the result given in my original post?
Bill Simpson
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#5
Oct24-13, 03:57 PM
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Lots of other programs can do that.
Computer Algebra Systems, like Mathematica, Sage, Maxima, Reduce, Maple... all do that.
http://en.wikipedia.org/wiki/Computer_algebra_system

Some calculator programs, like bc and many others do that.
https://www.google.com/search?q=big+...ger+calculator

Many programming languages, like Icon, Java... do that, don't be fooled by those who think 64 bits is big.
https://www.google.com/search?q=prog...ge+big+integer
Chronos
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#6
Oct30-13, 02:11 AM
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64 bits is chump change for deep calculations. You need a monster computer to process calculations beyond a few hundred decimal points. That is why numerical analysis takes so long and is so incredibly expensive.
harborsparrow
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#7
Oct30-13, 11:24 AM
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Just for grins, try putting the smaller number first.
phinds
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#8
Oct30-13, 03:00 PM
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Quote Quote by harborsparrow View Post
Just for grins, try putting the smaller number first.
Do you really think that's going to have any effect on the fact that the larger number is WAY bigger than Excel can handle as an integer?
harborsparrow
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#9
Oct31-13, 01:05 AM
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Quote Quote by phinds View Post
Do you really think that's going to have any effect on the fact that the larger number is WAY bigger than Excel can handle as an integer?
Sometimes it does help to prevent loss of precision by putting the smaller number first, when there is a huge range of magnitude difference between two operands.
phinds
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#10
Oct31-13, 08:10 AM
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Quote Quote by harborsparrow View Post
Sometimes it does help to prevent loss of precision by putting the smaller number first, when there is a huge range of magnitude difference between two operands.
Yes, and that does not answer my question at all. I am asking about a specific case.


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