Bookmaker's Numbers, also known as ODDS, are a numerical representation of the likelihood of an event occurring. They are used by bookmakers to determine the payout for a bet. The ODDS are usually expressed as a ratio or fraction, with the numerator representing the amount of money that will be paid out if the bet is successful, and the denominator representing the amount of money that must be wagered in order to receive the payout. For example, if the ODDS are 3:1, then for every dollar wagered, the bettor will receive three dollars if the bet is successful.