Method A: I think is 31 because you first have to get out of the negatives which is already 12, then you have to go to positive 19 which is 19 more, so add those and you get 31.
Method B: The absolute value of the difference between the two numbers is positive 31. This is because the absolute value of -12 is 12 and the absolute value of 19 is 19. Just add.