This is Anna.
Anna is hosting a party.
Anna invited 3 friends
Each friend brought more friends.
So she has friends at her party.
3 x =
Anna had teacups and her friend George brought teacups so they have teacups altogether.
+ =
With people at the party
there were extra teacups.
- =
there were people without teacups.
- =
Everyone got a cup and there were none left over.