Four Ball is a style of team golf often used in group competitions, including the Presidents Cup and Ryder Cup. Because the rules permit excellent play by one teammate to negate the less than sterling play of a partner, it considered strategically sound to pair an aggressive player with a consistent player. That strategy allows the aggressive player to take chances to score low, while the consistent player is there for a save should his partner's aggression backfire.
Compare the scores for each group of partners at the conclusion of a hole. Discard the higher score for each team. For example, if Team A has a 4 and a 5, the 5 is thrown out.
If Team B shoots a 3 and 7, the 7 is discarded. Team A wins the hole by a 3 to 4 score.