=concatenate function won't work

I have a simple spreadsheet where I want to use the =concatenate function to combine the text, “Dec”, in cell A1 with a blank space and the text, “1837”, in cell B1 to be put in cell C1. I have entered the following in cell C1:
=CONCATENATE(A1; " "; B1).
It will not return the result “Dec 1837” in C1. The cell just contains the above function. I have Data>Calculate>AutoCalculate checked and I’m using LibreOffice Version: 6.1.5.2 (x64) on a fully updated Windows 7 machine.
I assume I have something set incorrectly or not installed properly.
What could I be doing wrong?
I can supply a copy of the ODS spreadsheet if needed.
Thank you for your time and effort… Peter Bradish

Most probably your cell is dedicated to contain text by setting the (fake) Numbers format code @. Such a cell will keep anything you enter (including formulas) as a literal text.

I don’t understand what a “(fake) Numbers format code @” is. How do I determine this and what should I format the cell (C1) to?

Format Cells...>Numbers tab>List at the left under Category: Bottom item Text, if chosen, puts the @ into the format-code line. This doesn’t realy format numbers, but tells the cell not to apply a recognition process to entered/edited characcter sequences, but to take and keep them literally.
Cells containing formulas for evaluation must recognize them as formulas first. Therefore these cells must be formatted to a true Numbers format, A new recognition may require in addition some marginal editing.

Got it. It works now. Thank you very, very much. I had no idea. Had never run into that before… Peter

Please, if the answer solves the question click :heavy_check_mark:.