Linemakers who work for the sportsbooks must put out lines that will entice the "favorite" bettors to lay the points and take the favorite or entice the underdog bettors to take the points with the underdog. Because each sportsbook is operated under their own rules, guidelines and stipulations, they are free to put out whatever line they feel is competitive and charge whatever vig they want to based on how much action that specific line is taking.
In this baseball matchup, the St. Louis Cardinals are the moneyline favorite. For the bettor to win $100, he will need to wager $150, risking $150 to win $100. If the Patriots lose, the bettor will lose his original stake of $150. The Pittsburgh Pirates are the moneyline underdog in this matchup. A $100 dollar wager will win the bettor $140, risking $100 to win $140. Again, if the Pirates lose the bettor will lose his original stake of $100.
One of the most basic concepts when it comes to betting on sports, especially football and basketball is the pointspread. Even people that do not bet on sports understand what it means when they read or hear that New England is a seven-point favorite against Miami. While reading a pointspread and understanding what they mean is a very basic sports betting concept, there is still more to these numbers than meets the eye.
Apply the money line. It's easiest to think of money lines in relation to $100. A minus sign means you have to bet that much money in order to win $100; a plus sign means that a $100 bet will return that much money. If you bet on Chicago at -110, you'll have to wager $110 in order to get back $100 (plus your original $110). If you bet on Detroit at +145, then a $100 bet will give you $145 (plus your original $100).
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.