2 div's to adjust automatically depending which is in the first div

Long title I know but I don’t know how else to describe it briefly. Haha

I have 2 div's, 1 of which will have text in and I only want it to be as long as the text is, and the second to fill the rest of the inherit div. So say the inherent div was 1000px's long and the first div was 300px's in length to fit the length of the text inside, how do I make the second div to fill the last 700px's?  And it needs to be automatic because I need this in multiple pages, multiple times.

Thanks in advance, Matt

Humm can you provide an example or screenshot?

From the top of my mind i'd float the first div so that the content of the second is "wrapped around" it 

thanks man, i dont know why i blanked and couldnt think of that