(no subject)

[anfractuousity.livejournal.com]

Can someone explain to me what they mean here, when they say "double crochet/single crochet" and "treble crochet/double crochet"?

I'm not at ALL used to following diagrams, and the / isn't helping me any. Does that mean double crochet OR single crochet, depending on pattern? In which case, it's not very helpful. I'm so confused. Does it just mean you have the option of picking which you'd like to do for a different look?

Didn't notice the explanation at the top of the page. Heh.

Now I have another question. For example, in this pattern, what do the lines with numbers next to them mean? Like, the curved lines with 2s and 3s below them.

What do things circled in red mean?