Why in football do they have to run over 20 or 28 etc yards in 4 downs sometimes I thought they only had to take 10 yards can someone please explain this to you?

Answer 1

When given possession of the ball the offense is started off with ten yards to go on first down. As the team tries to get the next first down, sometimes penalties are accumulated and that adds yardage on meaning they may have to go more than the previous ten yards. There are also other times where someone on the offense loses yardage for the team while handling the ball and this pushes the line of scrimmage back far enough to make it more than the previous ten yards as well. So, there are times where you will see a 3rd and fifteen or a 2nd and twenty or even a 1st and twenty five.