Oddsmakers set a number of points by which a team is favored by. This number is called: the spread.
- Dallas Cowboys +6½ vs. Tampa Bay Buccaneers -6½.
In this example, the Buccaneers are favored by 6½ points.
You can either choose the favored team to win by more than the number of points set, or bet on the underdogs (Cowboys) to lose by less than the number of points set or win the game outright.