Prepositions of movement
At and in
At and in can also be used as prepositions of movement, but they're used to show the purpose of the movement.
I threw the paper in the bin.
Let's have dinner at my place.
When used after some verbs, the preposition at also shows the target of an action:
The bowler was sent off for throwing the ball at the umpire, instead of to the batsman.
!Note - a lot of sites say that around and round are the same, but there can be a difference, especially in BrE. If someone says "they were running around", it implies the movement is erratic.
For example: Children tend to run around at school.
In BrE when we use "round" we imply a more definite purpose and a more circular movement.
For example: The athlete ran round the track.