49 - 12 = 35
35 * 2 = 70
They scored 70 points in their first round game.
You start with the Championship Game score. This score is 12 points MORE than Half of the first round games score. So if you subtract 12 from the 49 points they got in the championship game then you would get 35 which is half of the first round games score.
Since 35 is half the score, if you multiply 35 by 2 you would get the total First Round Game score of 70.