Not exactly true cappytan. In football there are five different ways to score and each has its own point value:
the touchdown, the most desirable where the ball is advanced into the endzone dduring regluar play 6 points
then there is a "point after attempt" following a touch down. If the ball is kicked and the kick goes through the goal posts, 1 point is awarded. If the ball is advanced into the end zone via any other means (a run or a legal pass ), 2 points are awarded
A field goal is when is a kick attempt made when a team has regular possesion of the ball (meaning not a point after attempt) and if made 3 poimts are awarded.
lastly a play called a "saftey" is worth 2 points. A safety is basically when the team on def downs the ball in the offensensess end zone.
So not quiet so cut and dry as "21-24" ;)