Here is nice tips on how incoming and outgoing links gets calculated for a page. After watching this, I got how one page gets SEO rank from incoming and outgoing links.
In video Matt is telling that the links a page is getting create a weight (rank) for page. and What comes out divides those ranks. So, just to understand, I got like this: If a page gets 30 incoming links and he has 3 outgoing links then the page is worth 10 incoming links. There are more to know from the video.