I don't think that this is an error, although it is a bit confusing.

The 'number' 4 in the example spreadsheet is in fact text (try =istext(A4) ),
and thus would not be summed.

Try entering '4 which forces the 4 to be text. It is left justified. You can
right justify it to make it look like a number, but it isn't and will not sum

To insert a hyperlink you have to type 4 in the 'Text' box - and then you have
to right justify it to make it look like a number - but it isn't..

If this resolves the issue could you close it please? HTH

The problem arises, when I have a list of numerals in OO Calc with the sum()
being calculated and I attach a hyperlink to one of the numerals (perhaps
indicating the origin of this value).

Attaching the hyperlink converts the numeral into a text item which then  -
consequently - is omitted in calculating sum().

I was neither successful in attaching the hyperlink to the FIELD containing the
numeral itself (not to a part of its content)assuming this might leave the data
type unaltered, nor could I find a way to re-convert the text item to a numeric
value as long as the hyperlink is attached.

Best regards
Tom Novacek

Yes, I see what you're trying to do... I can't find a way to attach a 
hyperlink to a cell with a number either - but I think that Calc is working as 
it was designed to, so it's not a bug. Maybe you could make a request for 
enhancement? But just looking at an old copy of Excel, it doesn't allow 
hyperlinked numbers either.

Other ideas:
1. Presumably the hyperlinked data is static - you could simply add 4 to the 
SUM() ;)
2. Have the links in an adjacent column
3. Have a hidden column with numbers, possibly even =VALUE(), and SUM that
4. Aha! - use =SUM(VALUE(A1:A2)) , entering by pressing CTRL-Shift-Enter - an 
array formula, which will convert to numbers before summing. Should appear as  
{=SUM(VALUE(A1:A2))}

Does that solve it?

issue is fixed successfully.

The Issue you raised has been marked as 'Resolved' and not updated within the
last 1 year+. I am therefore setting this issue to 'Verified' as the first step
towards Closing it. If you feel this is incorrect, please re-open the issue and
add any comments.

Many thanks,
Andrew
 
Cleaning-up and Closing old Issues
~ The Grand Bug Squash, pre v3 ~
http://marketing.openoffice.org/3.0/announcementbeta.html

As per previous posting: Verified -> Closed.
A Closed Issue is a Happy Issue (TM).

Regards,
Andrew