thanatosdementor:

In Hp and the prizoner of azkaban when trelawney comes down for the meal she says that 12 ppl were at the table meaning that she could not sit, bc then there would be 13 and that would mean that the first person who stands up, is the first to die. But ppl seem to forget that Ron had scabbers in his pocket, making the ppl at the table already 13 before Trelawney came. 

and then dumbles stood up to pull out a chair for her.