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).
You can also bet straight winners and losers -- with no point spreads involved -- with money line wagers. When there is a minus number you bet that amount to win $100 in profit. When there is a plus number, that is your winning profit for every $100 wagered. So if the Cowboys have a money line of -250, you would have to bet $250 on them to win $100 in profit on any Dallas victory. If the Giants had a money line of +150, you would win $150 in profit with a winning $100 bet. If a money line is posted as even, you would win a $100 profit on a $100 winning bet.
The key here is to target the point spread five and seven, because these are virtually tied as the most common margins of victory. It's important to recognize that most betting sites are only willing to sell 2 or 3 half points for 10 cents each, after which point they start charging more. Some sites sell up to four half points at this price though.
Sports spread betting began in the United Kingdom in the late 1980s to offer an alternative form of sports wagering to traditional fixed odds, or fixed-risk, betting. With fixed odds betting, a gambler places a fixed-risk stake on stated fractional or decimal odds on the outcome of a sporting event that would give a known return for that outcome occurring or a known loss if that outcome doesn’t occur (the initial stake). With sports spread betting, gamblers are instead betting on whether a specified outcome in a sports event will end up being above or below a ‘spread’ offered by a sports spread betting firm, with profits or losses determined by how much above or below the spread the final outcome finishes at.
The first number in the listing pertains to the order this game appears on a sportsbook’s board. The next NFL game would be listed as #103 for the road team and #104 for the home team. You can think of these numbers in the same way that each horse in a race has its own betting number. The next big takeaway from this listing is that the top team is always the road team (thus the odd number) and the bottom team is playing at home.
The moneyline is different. First, with the moneyline whichever team wins the game pays out. There’s no giving or taking away of points. How do the bookies even the playing field with the moneyline? They do it by making bettors wager more on the favorite to win less and allowing them to bet less to win more on the dog. The favorite is posted with a minus sign and a number. That number represents the amount of cash that has to be wagered in order to win $100. The underdog, on the other hand, is listed with a plus sign in front of a number. That number shows how much a bettor wins when they bet $100.

It is a very good idea to shop around to find the best line when you are betting on sports. Books may offer slightly different lines, and you might be able to gain a point or half a point in your favor on certain markets. Consider an NBA game between the Heat and the Lakers – one firm has the Heat 9.5 point favorites and another have the Heat as 8.5 point favorites. You back the Heat with the second firm and they win by exactly nine points. Here you’ve gone from a loss to a win simply by shopping around, and in the long run this will make a big difference to your bottom line.
So the sportsbooks and bookies created a point spread to make both teams equally attractive in the eyes of bettors. Carolina was installed as a 6-point favorite, which is commonly written as Carolina -6. Denver, the underdog, is commonly written as Denver +6. In other words, Denver would be credited with whatever points they actually scored — plus six. If you bet the favorite, the Panthers would have to win by 7 points or more for you to win your wager. And remember, the Panthers are favored by 6 points, so we have to subtract 6 points from their final score for betting purposes.
Technically, probability should always be a number between 0 and 1. It's often expressed as a percentage though, which makes things easier for the purposes of betting. 0.7059 converted into a percentage (i.e. multiplied by 100) gives us 70.59%. What this means is that the odds suggest the Celtics have a 70.59% chance of winning. If we believe the Celtics have an even greater chance of winning, then we should back them at odds of -240.
You may have heard the term “covering the spread” or the phrase “betting against the spread.” This means that if the favorite team wins an event with the point spread taken into account or that the underdog team wins with additional points, they have covered the spread. If the Packers win that game by more than 7 points, they have covered the spread.