I just got back into comics after a few months or so and I am having a hard time catching back up particularly in the ".1" part. Let's focus on Amazing Spiderman and Invincible Iron Man. they have two of what seems to be the same issue Spiderman has 654.1 and 654 and Iron man has 500.1 and 500.
What's the difference? And which one starts the new story arc?