Bookie's calculations refer to the ODDS that a bookmaker or bookie assigns to a particular event. This is done by taking into account the probability of an outcome occurring and then setting a price for a bet on that outcome. The term 'ODDS' is used to describe the ratio of the probability of an event occurring to the probability of it not occurring. Bookie's calculations are used to determine the potential payout for a bet, as well as the amount of money that must be wagered in order to win a certain amount.