Does anyone know where I can get some practice in Boolean simplification or any type of digital work, like tests/quizes/practice problems?

But anyway I have a question. To practice on the simplification I tried to simplify a simple adder circuit I got from HSW http://computer.howstuffworks.com/boolean2.htm They show a simple adder circuit but then say that it isn't the best way to do it that it can be done with fewer gates, so I have been trying to simplify it. Could someone tell me if I am doing this right or what:

First I converted it into an equation...

For Q:

(AB'+A'B)C' + (AB+A'B')C =

AB'C'+A'BC'+ABC+A'B'C

Since there are 3 variables grouped together I can't figure out how to simplify it any further than it already is? Am I doing something wrong?

The (AB'+A'B) is the XOR gate of course. The (AB+A'B') is the XNOR gate correct? (Which I got like this:

(AB'+A'B)' = (AB')'(A'B)' = (A'+B)(A+B') = AA'+A'B'+AB+BB' = A'B' + AB ? with DeMorgans theorem)

For CO (Carry out):

(AB)C'+(A+B)C =

ABC'+AC+BC =

A(C+C'B)+BC =

A(C+B)+BC OR AB+AC+BC

I got this one down a little, but can it go any further and am I doing it right?

Sorry if this is the wrong section of the forum.

Thanks for any help.