real-life examples, such as horse racing, the pool size often extends into millions of dollars with many different types of outcomes (winning horses) and complex commission calculations. Sometimes, the amounts paid out are rounded down to a denomination interval — in California, Australia, and British Columbia 10¢ intervals are used. The rounding loss is known as breakage and is retained by the betting agency as part of the commission. In some situations, a negative breakage may occur. For example, in horse racing when an overwhelming favorite wins (or shows or places). The parimutuel calculation results might call for a very small winning payout (say, $1.02 or $1.03 on a dollar bet), but legal regulations may require a larger payout (e.g., minimum $1.10 on a dollar bet). This condition is sometimes referred to as a minus pool. Algebraic summary In an event with a set of n possible single-winner outcomes, with wagers the total pool of money on the event is After the wagering company deducts a commission rate of from the pool, the amount remaining to be distributed between the successful bettors is . Those who bet on the successful outcome will receive a payout of for every dollar they bet on it. When there are possible winners, such as a North American "place" bet which has winners, the total amount to be distributed is first divided into equal shares. If is one of the winners, those who bet on outcome will receive a payout of for every dollar they bet on it. History The parimutuel system was invented by Catalan impresario Joseph Oller in 1867. The large amount of calculation involved in this system led to the invention of a specialized mechanical calculating machine known as a totalisator, "automatic totalisator" or "tote board", invented by the Australian engineer George Alfred Julius. The first was installed at Ellerslie Racecourse, Auckland, New Zealand in 1913, and they came into widespread use at race courses throughout the world. The U.S. introduction was in 1927, which led to the opening of the suburban Arlington Racetrack in Arlington Park, near Chicago and Sportsman's Park in Cicero, Illinois, in 1932. Strategy and comparison with independent bookmakers Unlike many forms of casino gambling, in parimutuel betting the gambler bets against other gamblers, not the house, which necessarily implies that the bank cannot be broken. The science of predicting the outcome of a race is called handicapping.