Betting on sports can be as simple as putting your money on which team you think is going to win a game. And that wager, called a moneyline bet, is among the most popular and reasonable that a beginner – or even a seasoned bettor – can make.

But no matter how complex the bet, it's of paramount importance to know what the odds are. In fact, no principle is more fundamental to sports betting than knowing what the odds are – and what they mean.

Scroll up, and you'll find a whole lot of numbers positioned near what you'll probably recognize as a matchup between two teams or athletes. Scroll down, and you'll find out what those numbers stand for, in addition to various words of wisdom to make you feel like you know what you're doing, even if you're just starting out.

Placing your first online wager can be a bit intimidating. Every U.S. jurisdiction has its own rules surrounding sports betting, not every major sportsbook is operational in every state, and wrapping your head around what all of those numbers (i.e., odds) next to a given sporting event mean requires a willingness to learn.

Your education starts with the most important rule of all: Always gamble responsibly. Set limits before you play, stick to a budget and betting strategy, and never chase losses. And if you feel as though your behavior is getting out of control, call 1-800-GAMBLER or a state hotline.

Betting on sports can be a wonderful way to enhance a fan's entertainment experience, but a failure to stay disciplined can have unfortunate financial and emotional consequences.

Before you bet, it's essential to know whether you're doing business with a legal sportsbook that's been licensed in the state where you're wagering. There are a lot of illegal, offshore sportsbooks that look very legitimate to the naked eye but are extremely shady when it comes time to collect on a winning wager or simply withdraw your money. Meanwhile, licensed sportsbooks are required to have checks and balances in place to ensure that these interactions are as straightforward and transparent as possible.

When in doubt, find out who your state gaming regulator is and either find a list of licensed sports betting operators on their website or contact them to ask. Short of that, here is a list of several leading legal U.S. sportsbooks that have geolocation software in place which will allow you to bet or prohibit you from doing so, depending on where you're betting from: Bally Bet, bet365, BetMGM, BetRivers, Betr, Caesars, Circa, DraftKings, ESPN BET, Fanatics, FanDuel, Hard Rock Bet, and Sporttrade. 

If you want to bet online with these sportsbooks, you need to register for an account, a process that's relatively foolproof once you're on one of their websites or mobile apps. If you're betting in person at a brick-and mortar sportsbook, you needn't be an account-holder.

As for which of these sportsbooks you should bet with, there are numerous factors that go into that decision. Some offer generous sports betting promotions and special wager types you might not find elsewhere, while others are fairer to more frequent bettors who win consistently. But the basic rule of thumb is you want to bet with the legal sportsbook that's offering you the best odds – or potential return on investment – for the wager you want to make.

The gambling-related numbers you'll find on an online sportsbook's screen are typically either odds, point spreads, or totals – as in the total amount of points that are expected to be scored in a game. We'll get into point spreads and totals in-depth a little further down, but when it comes to odds, here's a simple explanation.

While fractional and decimal-based odds are used in Europe and the sport of horse racing, American odds tend to adhere to a +/- system. In simplest terms, + (i.e., +300) odds indicate that the team or athlete you are betting on is an underdog, which means they're not expected to win, while - odds (i.e., -300) indicate that the team/athlete is favored to win.

If, say, in basketball, a team is listed at -7.5, that means they're favored to win by 7.5 points. If a team is listed at +7.5, that means they're expected to lose by 7.5 points. The numbers represent a point spread, and the fact that half-points are often used in spreads for sports that don't allow for the scoring of half a point might correctly lead you to believe that you'll want to bet on either side of that spread. But we'll delve into that shortly.

What we want to explain here is what -300 or +300 means in terms of your expected monetary return. If you bet on a team that's listed as a -300 favorite, you'll have to bet $300 to earn a profit of $100 (or $30 to win $10). Conversely, if you bet on a team that's a +300 underdog, a $100 bet would net a profit of $300.

The most straightforward sports wager is called a moneyline bet. Here, you're simply backing one team or athlete to win a given event. If this team or athlete wins that event, then you win your bet, and if they lose, you lose as well.

If you think an underdog has a compelling chance of keeping things close but aren't willing to back them to win outright, a spread bet might be the wager for you. Here, if a team is favored by 7.5 points, it will be listed as a -7.5 favorite, whereas a seven-point underdog will be listed at +7.5. If you bet on the 7.5-point underdog to beat the spread, that means your bet will cash if they either win the game outright or lose by 7 points or less. If they lose by 8 points or more, so do you. But let's say you bet the underdog at +7 and they wind up losing by exactly 7 points. That's what's called a push, and your original bet will be refunded, as though you never made the wager in the first place.

While spread betting in football and basketball is fairly straightforward, in baseball, a "run line" is the terminology that's used to describe the spread, while in hockey, it's a "puck line." For example, if the NHL's Colorado Avalanche are listed at -1.5 against the Seattle Kraken, that means that in order for a puck line bet on Colorado to cash, the favored Avalanche must win by 2 or more goals. And if MLB's Houston Astros are -2.5 on the run line against the Texas Rangers, that means the Astros must win by 3 points or more to produce a winning ticket.

A total is the estimated number of points a sportsbook thinks two teams will combine to score during the course of a game. Betting either side of the total is commonly known as an over/under wager. If a sportsbook thinks the Chiefs and Bills will combine to score 48.5 points in a midseason matchup, an "over" bet would cash if they collectively score 49 or more, while an "under" bet would cash if the total is 48 or fewer.

Bettors who enjoy predicting outcomes that will reveal themselves weeks or months into the future might want to consider a futures bet. This can be as simple as making a summertime bet on which team will win the Super Bowl the following winter or wagering on the Atlanta Braves to exceed their projected season-long win total of 92 victories. A futures bet might also involve betting on a certain player to win MVP or Rookie of the Year, although there are some states that prohibit wagering on outcomes determined by votes (more on that in a bit).

Every year, you'll hear about wacky Super Bowl "props," like whether the coin toss will land on heads or tails, but prop bets are actually a fundamental part of any sportsbook's betting menu. There are many types of prop bets, but the basic thing to remember is that prop bets focus on a specific aspect of a game, like whether Player X will exceed a certain number of rebounds in a college basketball game or whether Pitcher Y will strike out more than six batters in a baseball game. There are also team props, like which team will be the first to score in an NFL game.

Parlay wagers involve multiple bets, or legs, all of which must hit in order to yield a profit. Let's say it's Sunday in Philadelphia and you whip up a three-leg parlay wherein the 76ers, Flyers, and Eagles all must win for your bet to cash. The odds of this happening are nowhere near as good as just betting on one of these teams to win, but because of that, the potential payout is far more lucrative. 

Parlays can take on many shapes and sizes, including those that take multiple days to play out. But in America, same-game parlays (or SGPs) have become all the rage. With SGPs, the outcome of your parlay wager will be known by the time the game is over, since each leg is based on that very game. For example, a three-leg SGP – and parlays can involve as many legs as you want them to, with a minimum of two – in a Knicks-Bucks game might be for New York's Jalen Brunson to record 9 or more assists (leg one), with the Knicks covering a 3-point spread at home (leg two), and Giannis Antetokounmpo scoring more than 32 points for Milwaukee (leg three).

Did you fail to get your moneyline bet in before the first pitch of the Cubs-Cardinals game? That doesn't mean you can't still bet on it. Live, or in-game, betting is as viable an option as placing a pre-game wager. With live betting, odds will fluctuate in real time based on what's occurring during the course of a game, but you lock in the price shown at the time of your wager.

There are other types of bets that are more sophisticated, but this should be enough to get you started. Whether you're at a brick-and-mortar sportsbook or wagering online, if you're ever unsure about something, don't hesitate to ask someone who works there. They want your business in a competitive marketplace and are conscious of the fact that becoming a confident, competent sports bettor takes time.

Each state has its own catalog of sporting events that have been approved for wagering by the state regulator. This catalog typically includes all major American sports and a whole lot of minor or international ones, such as jai alai, field hockey, and Australian Rules Football. Some states even allow for wagering on entertainment-industry award shows like the Oscars and Grammys.

Not all sportsbooks will offer wagering on each and every event that's been approved in a given state, which reinforces the need to shop around for betting opportunities on niche sports. And just because a type of bet is legal in one state doesn't mean it will be in another. Several states don't allow prop bets to be placed on college players or games, while others won't let bettors wager on competitions involving in-state colleges. There are also states that prohibit betting on the annual player drafts held by the NFL or NBA, while a handful don't permit wagering on end-of-season awards or Olympic-style competitions where the outcomes are determined by a vote or panel of judges.

Simply put, if a type of wager is on a state regulator's menu of approved bets, it's allowed. If you don't see it there, you probably can't bet on it. And when in doubt, it never hurts to ask a sportsbook employee, whether in person at a retail counter, via phone or email, or through the chat function on a mobile app.