I have some questions like if $P$ then $Q, P$ therefor $Q$ for example, how can you tell from writing your truth table if therefor $Q$ is valid or invalid? I mean I know its true because Modus Ponens tells me it is but that doesn't really help on more complex issues like;
p∨q r r → ¬q −−−−−− therefore p
I can make a table but what am I looking for in it to show me therefore p is valid or invalid.
As per conversation with amwhy is this an accurate reflection of what you are trying to explain? I can see that the column with all true R is also true. Therefore its valid!