We have been given that the football team gained 4 yards on a play, lost 8 yards on the next play, then gained 2 yards on the third play.
Gain can be represented by plus and loss can be represented by minus sign.
Thus, we have
gained 4 yards means +4
lost 8 yards means -8
gained 2 yards means +2
Therefore, the addition expression to describe the total change of yardage is given by

Now we have

Thus, we have

We got minus sign, which means loss.
Hence, the football team lost 2 yards.