If subject is plural(we,you) shall the noun which is subject to the action be plural as well?
We are eating an apple.(Suppose we're sharing 1 apple.)Shall I say "estamos comiendo manzana" o "estamos comiendo manzanas." I suppose it should stay plural or singular depending on the noun. If you want to say we're watching a TV you shouldn't say "estamos viendo televisors" right? or what should you say?
I seem a little confudada, aren't I?
I would say "Estamos comiendo una manzana" for one shared apple. "Estamos comiendo unas manzanas" for we are eating some apples. If you are only watching one TV then it's not "televisors" I would say "Estamos viendo la televisión".
You would say "Estamos comiendo una manzana." The adjective agrees in number with the noun it describes. In your example, you are making a point to say you are sharing one apple, thus "una" is helpful in clarifying that you do mean one apple.