These odds are expressed using a minus or plus sign attached to a number and usually just indicate how much you’d need to stake to win $100 (if the odds are positive) or how much you could possibly win from staking $100 (if the odds are negative). “American Odds” is the term given to the odds format used by bookmakers offering sports betting services in the U.S. “Odds” are the numerical representation of the probability of an event occurring. To understand how American odds work, one must first grasp the concept of odds.