Another type of roulette is the European wheel which is also known as the Single Zero roulette or sometimes French Roulette and it's resembles the American wheel.
The fact that European wheel only has a single zero - whereas American wheel has a single zero and a double zero, makes the biggest difference between these two.
As the red/black and odd/even are placed right next to each other, and the first18/last18 betting spots are placed right next to the single numbers on the american table it is more practical during the game, but the European table is more more beautiful in symmetry.
The European single zero offers the player better odds than the American wheel with it’s single and double zero.
There 38 numbered slots on American roulette wheel: numbers from 0 to 36 and 00. The betting layout consists of every individual number as well as a host of "outside" or combinations of numbers. After the players make their bets the dealer spins the wheel and a ball and after several seconds the ball will land in one of the numbered slots.

The Martingale is the best-known roulette betting system. It varies greatly. The main idea of the system is that when you win, you pocket your bet. But when you lose, you double the size of your previous bet.If you win that will guarantee you get back your previous loss and one more unit.And so on.
The Martingale System is effective only if you have an infinite bankroll and no betting limits.
Another popular roulette system is the d'Alembert system. The system is based on the assumption that after a win you are less likely to win again.So after a win, you subtract a chip from your bet. The d'Alembert system also assumes that you are less likely to lose after a losing spin, so in that case, you add a chip to your bet. The fact that the roulette wheel has no memory and each spin is an independent trial with exactly the same odds of a win or loss is the previous spin is a weak point of the system.

The numbers 1 through 36 are divided evenly among red and black "pockets" on the Roulette wheel. The ball will land in one of the pockets. The Roulette wheel also has on or two green pockets. The green pockets has numbers 0 and 00 or only 00, depending on the kind of Roulette.
The Roulette wheel is spun by the dealer in the counter clockwise direction and then he releases a plastic ball along the top of the wheel’s cavity. The wheel loses speed and as a result the ball comes down from the track, bounces a little and then lands in one of the pockets.