When the point spread was invented in Chicago by Charles McNeil the money line took a backseat. When two unevenly matched teams played, the playing field was leveled by having the favorite give points (for example Chicago Bears –7) while the underdog got points (Minnesota Vikings +7). No matter which team the bettor took the bettor would always risk $110 to win $100. The extra $10 needed to win $100 is called the juice or the vig, it is basically the house’s or the bookie’s take. It’s 10-percent of the bet so it would take $33 to return $30 and $440 to return $400 etc. (winning bettors get the vig back).
Let's take a look at a sample Asian handicap bet to make this make more sense. Some things are just better learned through getting your hands dirty. For example, imagine that you choose to bet Manchester United at (-1, -1.5). Half of your bet would be for Manchester United at -1, and a half would be at Manchester United -1.5. Let's say Manchester United wins the game by one goal. You would push on your first bet and lose on your second bet. If you bet $100 on this, you would receive $50 back for the push and lose on the other portion of your bet.
All point spreads are set by the pool administrator. NOTE: The administrator has the power to change the point spreads at any time up until 15 minutes before the start of the first game, so make sure you know when the administrator will make the final changes. For your own information you should also find out where the administrator is getting their point spreads.
In this example, we have a favorite to win, and an underdog. The Packers are the favorites, and that is shown by the (–) value in front of the 6. Underdogs are represented by the (+) value.  The 6 point value is how many points either team could win, or lose by. If you think the Packers will win by MORE than 6 points, then you’d bet on the favorite in this case, meaning that the Packers have to win by 7 or more points in order for you to win your bet.