To enhance efficiency, Cisco IOS Software has some shortcuts for entering commands. Although these are great to use in the real world, when it comes time to take the CCNA 200-301 exam, make sure you know the full commands, not just the shortcuts.
Router> enable = Router> enab = Router> en
Entering a shortened form of a command is sufficient as long as there is no confusion about which command you are attempting to enter
Router# configure terminal = Router# config t