Have the sum of 12 months of data and now want to copy just that number to another file where I can use that number in another application. Now when I try this I get something like “#REF!” in bold print.
Your question doesn’t seem to be related to LibreOffice Base (tag: base) but to Calc (tag: calc)
use that number in another application. Now when I try this I get something like “#REF!”
Which other application could show an "#REF!" error? You may get that if you copy to another spreadsheet but generally not, if you copy to another application.
Have you tried Paste Special > Paste Unformatted Text (Ctrl+Alt+Shift+V)?