1.Who is talking to you?
3.What do you listen to with them?
4.Where do you practices Spanish with me?
Declarar! It’s like say that you are passing through the airport with smth and you have to do it there, so, tienes que declarar en la aduana
I don't fully understand your question, however if referring to spaniah class, or math class it is clase de español, and clase de mathematicas