LibreOffice Calc is the spreadsheet application in the LibreOffice suite. In LibreOffice Calc, if the cells of a spreadsheet hold the results of formulas, then those results cannot be copied and pasted to a different cell. This is because the formula is copied instead of the result.
To copy the results of the formulas instead of the formulas themselves, do this:
Copy the cells as usual.
Right-click at the cell where you want to paste the results and choose Paste Special.
In the Paste Special dialog, under the Selection section, uncheck all the different types of selection. Check only Numbers (assuming that the results are numbers). Choose OK.
The results of formulas should be pasted now instead of the formulas. This trick can also be used to do in-place replacement of cells with formulas with their results.
Tried with: LibreOffice 18.104.22.168