Sometimes a student inadvertently turns on full zoom maginification by keystroke. This is really easy to turn off, just follow these steps.
go to the bottom right hand of your screen and look for this
Click on anywhere in that area
and you will see this
you want to see the word ACCESSIBILITY click on the little arrow next to it
and next shows this
Full screen maginifier will have a green check mark next to it.
Unclick that green checkmark and it will go away and you device should be no longer zoomed in