There are two different roulette wheels commonly used in casinos.
The European wheel has 37 slots
numbered 0-36.
The American wheel has 38 numbers because of the added double zero (00) number.

The game of Roulette originated in France. The modern day layout we find in the casino dates back to 1842. Roulette layouts have two betting areas. The inside betting area contains the individual numbers on the layout. The outside betting area has boxes for the columns, red/black and odd/even and different groups of numbers.
The numbers on the inside are arranged in 12 rows (called "streets") of three numbers while forming three vertical columns. They are marked with the 2 to 1. The 0 and 00 are at the top of the columns.


Some casino roulette tables have an electronic marquee that displays about the last 20 spins of the roulette wheel. The casinos have made a lot of money since the advent of the "scorecard". Players can easily see streaks and try to bet for them or against them.
The number on top is normally the last spin.
another example