Odds for different outcomes in single bet are presented either in European format (decimal odds), UK format (fractional odds), or American format (moneyline odds). European format (decimal odds) are used in continental Europe, Canada, and Australia. They are the ratio of the full payout to the stake, in a decimal format. Decimal odds of 2.00 are an even bet. UK format (fractional odds) are used by British bookmakers.
They are the ratio of the amount won to the stake - the solidus "/" is pronounced "to" for example 7/1 "seven to one". Fractional odds of 1/1 are an even bet. US format odds are the amount won on a 100 stake when positive and the stake needed to win 100 when negative. US odds of 100 are an even bet.