You would start out at in the middle of a number line (horizontal). After the first play, you would move to the left on the line 5 spots (to simulate 5 yards lost) and then make a dot to show your new position. You would do the same thing for the next two plays, moving 5 spots to the left each play and creating a new starting point each time. The total spots moved after the 3 plays is 15 spots to the left.