Apps displayed in small window mode on iPad (Multitasking Mode)

Students can sometimes trigger Multitasking unintentionally- one way that seems fairly easy is by sliding a finger from the right edge of the screen.

To get rid of the overlaying app, hold your finger on the line at the bottom of the 'window' of the app that is on top of the app you want to use and drag it upwards sligtly. This should put the app in the center of the screen and you can then swipe the app up and away completely which reset the app into its normal mode.

If a student repeatedly winds up triggering it you can turn off multitasking gestures in Settings > under "home screen and Dock" just turn off the option "allow multiple apps".