The negative (-) sign indicates that the Cowboys are the favorites, while the positive (+) sign indicates that the New York Giants are the underdogs. With the spread set at 2.5 points, a bet on the Cowboys would mean that they would have to win by more than 2.5 points (3 or more) in order for you to win that bet. A bet on New York would mean that the Giants would have to either lose by 2.5 or less points (2 or less) or win the game outright in order for your bet to win.

Proline will set a point spread for each game of either -0.5 / +.05, -1.0 / +1.0, or -1.5 / +1.5. If you choose -0.5 the team must win by 1 goal or more to win your wager. If you choose +0.5 your team must win or tie the game. Note that OLG Proline includes the shoot-out for point spreads so there are never any ties for the -0.5 / +0.5 spreads.  If you choose the -1.0 spread your team must win by 2 or more goals to win the bet. If they win by 1 goal exactly it is a push. If you choose the +1.0 spread your team must win the game by 1 or more goals. If they lose by 1 goal it is a push. If you choose the -1.5 spread your team must win by 2 or more goals. If you choose the +1.5 spread your team must win the game, tie, or lose by 1 goal to win the bet.

Now Arkansas can lose by up to eight points, and you can still win a bet on Arkansas. As the Arkansas line gets more appealing, more people will start to bet that side. The sportsbook will continue to manipulate the line this way up until game time to try and get the bets as even as possible. While they won't be perfect about it, they can usually get it close enough in most situations. It's also important to note that the line will sometimes shift by half points and it's also capable of shifting back in the other direction if too much money comes in on the other side.
Let’s say that people think the Mavericks are going to crush the Magic, and the money starts to pour in on the Mavs. Obviously, the sportsbook likes seeing a lot of bets come in, but they need them to come in evenly. So, to slow down the money coming in on the Mavericks and entice people to bet on the Magic, they will shift both lines. The new line might look something like this:

We went into detail earlier about what causes moneylines to move. The better you can get about predicting when these movements will occur and in what direction, the more profitable you’re going to be as a sports bettor. If you find a bet that you like, but you predict it’s going to move more in your favor, you can intelligently wait to bet and lock up a potentially much more profitable opportunity.

You’ll need to know how the rotation number, point spread, moneyline and over/under are used and what each means. Each of these terms may be called by another name. The rotation number if often referred to as the number or the rotation mark, moneyline becomes line, point spread is called the spread, and over/under becomes the total. When you come down to it, these are the major terms that can be lumped under the heading odds.
When two teams square up for a matchup, whether that be on the gridiron or on the basketball court, one team is typically better than the other (for whatever reason you want to believe). Since sportsbooks are in the business of making money, they tag the better team with a point spread, thus making them the "favorites" to win that specific game. Normally, the favorite has a few favorable factors working for them like playing at home or being well rested or playing a revenge game against a team that previously beat them. Every factor counts in the world of betting, and it's up to you to decide if the "favorite' can, in fact, cover the point spread.
Understanding NFL betting lines is just the first step towards making profits with football wagering. Once you've got the basics down, it's important to continue learning sports betting strategy to improve your long-term chances of winning. If you're able to win more than 52.4% of the time, you'll be well on your way towards being a profitable NFL bettor.
They do this by manipulating the lines to entice action where they need it. If they have too much action coming in on one team, they will adjust the lines to pay out less for that team to deter more bets. At the same time, they will adjust the line for the other team to pay out more to entice more action on that side. This dance continues until the game starts to try and get the correct amount of money on each side of the contest.
Baseball, soccer, and ice hockey are mostly moneyline betting, since these sports do not have point spreads moneylines are the default way of wagering. Football and basketball do have moneylines in addition to point spreads. In recent years, football moneylines have become extremely popular among sports bettors. Moneyline betting is based on the amount bet per $100. Let’s look at look an example of a baseball moneyline:
Armed with the knowledge of how to remove vig, it's now possible to prevent yourself from making the same mistakes that the majority of bettors make. Most bettors understand the importance of line shopping (i.e. comparing the lines and odds at different bookmakers and betting sites). However, if they fail to also understand how moneylines and vig work, then they're probably going to make wagers where they think there's positive expected value (+EV), even though there's not.

Because the Blue Jays are favored, the sportsbook needs you to risk more to bet on them. After all, they should win this game. So wagering on baseball favorites with moneylines calls for you to risk a certain number ($185 based on -185) in order to win $100. On the other side, the sportsbook is also willing to reward you for taking the underdog, so they give you an incentive to bet on the Orioles. In this case, you would risk $100 in order to win $165 (+165) on Baltimore.
In North American sports betting many of these wagers would be classified as over-under (or, more commonly today, total) bets rather than spread bets. However, these are for one side or another of a total only, and do not increase the amount won or lost as the actual moves away from the bookmaker's prediction. Instead, over-under or total bets are handled much like point-spread bets on a team, with the usual 10/11 (4.55%) commission applied. Many Nevada sports books allow these bets in parlays, just like team point spread bets. This makes it possible to bet, for instance, team A and the over, and be paid if both team A "covers" the point spread and the total score is higher than the book's prediction. (Such parlays usually pay off at odds of 13:5 with no commission charge, just as a standard two-team parlay would.)
Let’s say you decide to bet $100 on the Packers to win by more 7 points and the final score is Packers 30, Seahawks 21.  The Packers have won by 9 points, meaning they’ve covered the spread, and you’ve won the bet. The -110 means that your $100 bet will win you a total of $190. That total includes your original bet amount, so your total profit is $90.