will be given back to bettors and 10% goes to the bookmaker. Naturally the more money bet on a certain result, the smaller the odds on that outcome become. This is similar to parimutuel wagering in horse racing and dog racing. Half bets. A half (halftime) bet applies only to the score of the first or second half. This bet can be placed on the spread (line) or over/under. This can also be applied to a specific quarter in American football or basketball, a fewer number of innings in baseball, or a specific period in hockey. In-play betting. In-play betting, or live betting, is a fairly new feature offered by some online sports books that enables bettors to place new bets while a sporting event is in progress. In-play betting first appeared towards the end of the 1990s when some bookmakers would take bets over the telephone whilst a sports event was in progress, and has now evolved into a popular online service in many countries. The introduction of in-play betting has allowed bookmakers to increase the number of markets available to bet on during sports events, and gamblers are able to place bets based on many types of in-game activity during the matches. For example, in football matches, it is possible to bet in on in-play markets including the match result, half-time score, number of goals scored in the first or second half of the game, the number of yellow cards during the match, and the name of the goal scorers. The availability of a particular sport and in-play markets varies from bookmaker to bookmaker. In-play sports betting has structural characteristics that have changed the mechanics of gambling for sports bettors, as they can now place a larger number of bets during a single sports game (as opposed to a single bet on who is going to win). One of the most important differences between being able to place an in-running sports bet opposed to a pre-match bet is that the nature of the market has been turned what was previously a discontinuous form of gambling into a continuous one. The gambling study literature has suggested that in-play sports betting may offer more of a risk to problem gamblers because it allows the option for high-speed continuous betting and requires rapid and impulsive decisions in the absence of time for reflection. There are three different types of in-play sports