How many downs does a team get to move the ball up and down the field?

Teams get four downs to move the ball 10 yards. If they gain the 10 yards, they get a new set of four downs. This can continue indefinitely until either the team scores, time runs out in the half or the game, or the team gives up or loses possession of the ball.

In Canadian football, teams get three downs to move the ball 10 yards.