Odds of 1 to 1
The fractional odd 1/1. A bet of £10 at evens would win £10, and your returns would be £20 (which includes your stake back.)
An even-money bet on the ball to land on any one of the even numbers on the table.
A bet where the odds are 1/1 fractional or 2 decimal. Basically you double your money if you bet on this and it wins.
A bet placed on any of the even numbers. For example: 2, 4, 6, 12, etc.
A straight 1/1 bet. Bet £1 and you win £1 (plus your original stake money back).
or 1:1 bet. When your stake brings equal winnings - for example £10 evens wins £10