"Command Key will only give Math Symbols, not perform regular commands."

I saw this post and was experiencing the same problem and might've gotten to a solution:

"someone dumped some heavy papers on my keyboard a couple of days ago and ever since then the Command Key will only display symbols and not perform regular commands.  ie. instead of pasting, Command V just gives a square root symbol.  Instead of copying, Command C gives a small letter 'c' with a cedilla.  In other words, just math symbols.  It's very annoying and no aid to productivity.  Has anyone got any idea how I can restore the functionality of my Command Key (it doesn't matter what keyboard I attach to my Mac, I get the same problem)."

If in this situation you are using a bluetooth keyboard, check if the format of the command button is set to "Mac" and not "Windows". Under the windows setting on a bluetooth keyboard; you get a √ instead of pasting when attempting Command+V . To verify if the problem is due to a keyboard format issue, try Option+V. If that works as paste, then you're on the wrong setting. I hope this helps!!