Geogebra installieren Ubuntu 18.04

• sudo apt-add-repository -u 'deb http://www.geogebra.net/linux/ stable main'
• Falls Probleme mit Pub_Key:
  sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys NummerDesKeys
  sudo apt-add-repository -u 'deb http://www.geogebra.net/linux/ stable main'
• sudo apt update
  sudo apt install geogebra-classic