How long does it take a teacher to ask the children to gather 'round?
Here's a recent example from an excellent professional with eyes in every part of her head:
"Boys and girls - get your head out from under there - I'd like you to - no, this way, come down here - come up - please get off the table, thanks - and sit under - it's only a stinkbug, it won't hurt you - the Smart Board - stop chewing on your shoelace - so that we - honey, keep your hands off the computer - can - RIGHT NOW! - do the lesson - yes I know we did this last week but we're doing it again. Thank you!"
It's truly multitasking at its finest.