This is a basic addition/subtraction question. It's saying that they started at the 50 yard line. On the play, they gained 7 yards. So, we'll add 50+7 = 57.
They're at the 57 yard line at this point. On the second play they lost 10 yards (how unfortunate). Thereby, we will subtract 57-10=47.
50 yards +7 yards. -10 yards.
The answer will be that they'll be on the 47 yard line on the next play.
