Major League Baseball is back. With legalized sports betting available in 20 states (and Washington D.C.), America's pastime may induce more bettors than ever before. And with a full, 162-game season on tap, there are plenty of betting opportunities.

Football and basketball make life easy for bettors, as a point spread is the great equalizer and fairly easy to follow. If you bet on a team that is a five-point favorite, that team must win by at least six points for you to win the bet. A bet on the underdog necessitates that team to win the game or lose by four points or less. If the favorite wins by exactly five points, bets placed on either side are refunded. Baseball betting requires a little more math but it is less confusing and intimidating than many realize.

Here are the basics for betting baseball:

Money line

Baseball betting primarily revolves around the odds for a team to win, also known as a money line. Everything is in relation to $100.

So if the New York Yankees are playing the Detroit Tigers, the Yanks might be -250 favorites. The minus sign denotes the favored team, much like we see with a point spread, and means that you must risk $250 for every $100 you want to win. That's because the Yankees are considered to have a better starting pitcher and/or lineup, among other reasons. In this example, the Tigers are +200 underdogs, which means that if you risk $100 on Detroit, you win $200 if it upsets the Yankees.

Run line

Baseball also incorporates a point spread, and it is commonly known as a run line. Using the above game as an example, the Yankees could be -1.5, -140. That means the Yankees not only have to win the game but they have to win by at least two runs for you to win your bet. Plus, you are laying odds by risking $140 for every $100 you want to win. Basically, sportsbooks provide the bettor an option of making New York's win more difficult (margin of victory of at least two runs) instead of laying a larger money line (-250).

Total

Similar to football and basketball, baseball also offers an over/under, or total. This is a simple concept; it reflects the total runs scored. So if that Yankees-Tigers game has a total of 9.5, you can bet over or under. If the Yankees win 10-0, an over bet cashes. If they win 9-0, the under cashes. It is merely adding the total amount of runs scored by both teams, regardless of who wins the game.

First 5 innings line

Additionally, betting the "First 5" line is also an option. This line means you are solely wagering on the outcome of the game's first five innings. This usually happens if you want to isolate a starting pitching matchup and/or prefer to avoid bullpens. Unlike a regular game bet, bets on the first five innings money line can tie, or "push." If that occurs, your bet is refunded. The odds for these bets are similar to the odds on the full game. To reference the example from above, the Yankees could easily be -250 on the "First 5" line as well. Books also offer "First 5" totals.

Prop bets

Much like we see in other sports, baseball also offers proposition bets. They are fairly simple in concept. For a starting pitcher, you often have the option of betting over or under a certain number of strikeouts. Sometimes books offer a line for a key player's total number of bases. Another intriguing option is a team's over/under for the combined total of hits, runs and errors. A few examples:

Gerrit Cole: over/under 7.5 strikeouts

Mike Trout: over/under 2.5 total bases

Yankees (Hits + Runs + Errors): 28.5

House rules to know

There are some funky rules to baseball betting, so it's important to familiarize yourself with the house rules. For an over/under or run line bet to be valid, the game must last at least 8.5 innings. That means, if a team leads 15-6 and rain ends the game after seven innings, all bets on the total (and run lines) are refunded -- even if a game already hit the over. Bets on the regular money line are still graded; however, they are graded according to the last completed full inning.

Additionally, another caveat is the pitching option when placing a wager. A starting pitcher plays such a significant role in baseball that sportsbooks allow you to ensure the scheduled pitchers take the mound. When placing a wager, you can "list" the scheduled starter for either team or both. If you decline any of those three options, you have "action" on the game regardless of who starts but in the event of a pitching change, you automatically get the book's reposted odds. If you do choose an option of listing a certain pitcher and he is scratched, your ticket is refunded regardless of the game's outcome.