Just for dwivian

Help!  I know one of my books showed how to convert binary to hexadecimal, but I can't find it.  No idea how this is done and I'm in the process of reading about IPv6 addresses.  Because I've not had a good explanation of the conversion process, I'm just not getting the numbers.  I know that 0=0, 1=1 up to 9=9 then a=10, b=11, c=12, d=13, e=14 and f=15, but changing that to binary notation just isn't working for me.  Help!