View Single Post
  #5   Report Post  
Posted to microsoft.public.excel.misc
danieldc danieldc is offline
external usenet poster
 
Posts: 6
Default Sum - Sum < Zero ??? How is it? Bug in Excel formula?

On 29 mar, 17:08, Dave F wrote:
Here's an example of rounding errors:

I have in the formula =LN(RAND()^2) in C2:E5 and then I sum C2:C5, D2:D5,
and E5 and then do your formulas in A1 and B1. So far, everything is as you
create it.


Yes, you got it.


As you can see these are not equal but only very approximately equal, due to
Excel's 15 digit of precision calculation limit.


I had believed that Excel's 15 digit limit of precision calculation
could be enough...
But now, I changed my mind.

I will put some "truncate()" function at all places when I need
"exact" values.

Maybe that truncate(A1; 2) = truncate(B1; 2) will be always evaluated
TRUE.

yours, Daniel
from Brazil