On three consecutive passes, a football team gains 5 yards, loses 21 yards, and gains 13 yards. What number represents the total net yardage?

what is

5-21+13 ?

The Total Net Yardage is___ yards. ????

would the answer be -3.

Right. The team lost 3 yards.

To get the total net yardage, you need to add up the positive yardage gains and subtract the negative yardage losses. In this case, the team gains 5 yards, loses 21 yards, and gains 13 yards.

Let's add up the positive yardage gains first:
5 + 13 = 18

Now subtract the negative yardage loss:
18 - 21 = -3

The total net yardage is -3 yards.