Numbers

The teams, what they do, and their playing positions (formations)

While only eleven players per team play at any one time, most professional teams will have squads of forty-five players. This line-up usually consists of an offensive team, a defensive team, and a special team. There will also be reserves.

Players wear numbered shirts according to their playing position, whether they are playing offense or defense.

1-19 - quarterbacks and kickers
20-49 - running backs and defensive backs
50-59 - centers and linebackers
60-79 - defensive linemen and interior offensive linemen (including centers)
80-89 - wide receivers and tight ends
90-99 - further defensive linemen and linebackers