Ubuntu Mobile OS Tablet/Phone ~ Can it Apps from the Repository?

Sorry if this has been asked before but... I keep reading that the app selection for Ubuntu Phone & Tablet doesn't compare to Android and iOS.

Not a problem since I use one or two android apps at most; but then I also read that Ubuntu's Mobile OS can't run most of the software in the Ubuntu Repository? Am I understanding that correctly? For instance, I can't download LibreOffice or Calibre on an Ubuntu Tablet or Phone?

Am I missing something?

Edit: Meant to write 'Can it run Apps from the Repository?'