What are "American odds"?

In the U.S. a bet is determined from the "US$ 100 perspective". Favourites are displayed with a minus (-) and underdogs with a plus (+). For example: Odds +130 mean you must stake 100 USD in order to win 130 USD. Odds -150 mean you must stake 150 USD in order to win 100 USD. This is only for winning calculations. Your stake does not have to be 100 USD for every bet. With American betting interpretations, only the net winnings are quoted. To calculate the total payout, you must add your initial stake.