Baseball games are divided into segments called INNINGS. Each inning is composed of two halves, the top and the bottom. During each half, one team bats while the other team fields. The team at bat attempts to score runs by hitting the ball and running around the bases, while the fielding team attempts to prevent runs by getting batters out. After both teams have had a turn at bat, the inning is over and the teams switch roles. A regulation game consists of nine INNINGS.