Rule
8. Addition (Abbreviated by "AD") If "P" is an available line, any formula "Q" (available or not) can be added to P by putting a wedge "v" between them to make a new sentence "P v Q" which may be written as a new line. (Rules 713 are conveniently listed on Logic Rules Sheet Two ) 
Rule
9. Commutativity (Abbreviated by "CM") If any disjunction or conjunction is an available line, then that formula may be written with the postions of its conjuncts or disjuncts reversed. (The operator may not change.) Thus: If "P ^ Q" is an available line, then "Q ^ P" may be written as a new line. If "P v Q" is an available line, then "Q v P" may be written as a new line. (Rules 713 are conveniently listed on Logic Rules Sheet Two ) 
Practice 9. Use your own paper or the answer
sheet at practice.
Circle the valid arguments, and cross out the invalid ones.
Derive all three of these arguments
