誰か or 誰かが?

[lucagalbu]

Hi all!
I'm new in this forum and I've been studying Japanese for two years. I have a lot of question and I've just discovered this great forum!
I can't understand how to use 誰か; which of this sentence is the correct one?
1) 誰かがいます。
2) 誰かいます。
I mean, I have to express the subject ga-posposition or is it dropped?

 

[Toritoribe]

Both are equally correct.

 

[lucagalbu]

Thank you!
So, also
1)何かを買いました。
2)何か買いました。
are both correct?

 

[Toritoribe]

Yes, both are correct.

 

[lucagalbu]

Thank you

 

[nice gaijin]

you can drop particles as long as the context is sufficient for the listener to understand.