question about line numbers in patches

[alex wallis]

Hi list.
I've been looking at a few rb patches and was just wondering something about 
the line numbers.
I've been reading about patches on google so i no that the @@ sign shows 
where a patch should begin with in the file being patched. I was wondering 
though when I was looking at a few rb patches I'm guessing the big number 
shows the line that the patch is supposed to begin on. for example i'm 
guessing that in a patch i've been looking at 7329 means that line in a 
file. However I was wondering two things, in the particular patch i'm 
looking at and in all patches i've scene after the big line number there is 
a , then another number. I was wondering what does the smaller number after 
the , mean?
Also why is there a a - and a + sign used before the numbers. For example 
@@ -41,6 +41,8.
thanks for your help.
Alex.