Most casinos will usually have a selection of a few different versions on the roulette available to players. Fact is, there are pretty big differences between the different versions in terms of the probability of winning over time.
The different version of roulette differ with they number layout. The American roulette has 2 zeros (0 and 00), the European roulette has one (0), and the french roulette has one zero as well, but it pays back half of the bet if that number turns out and you haven't placed your bet on it.

Because of these changes, the 3 versions offer different odds of winning, and over time, this makes a pretty big difference. To figure out the house edge, we'll build a formula and agree on the following:
1.We're betting on Black.
2.We're betting with $1.

This is the American Roulette:
(-1 x 18/38) + (-1 x 18/38) + (1 x 18/38) = -.0537

This is the European Roulette:
(1 x 18/37) + (-1 x 18/37) + (-1 x 1/37) = -0.027

And finally, this is the french Roulette:
(1 x 18/37)+(-1 x 18/37)+(-0.5 x 1/37) = -0.014

The results tell us how much we're going to lose on average per bet. If we consider the American roulette, the result tells us that for every dollar we put on the table, we'll lose an average of $0.537.
The same reasoning applies for the European and French roulette as well, and clearly the American roulette should be avoided for its inferior odds of winning.