The purpose of roulette is to try to predict the outcome of where the white ball will land on each spin of the wheel. If we could only try to guess what number that was, the game would be a bit boring, as there would be no variety and it would get way too repetitive. Fortunately, the designers of the game have built in tons of betting options to make the game much more exciting, versatile, and downright fun. Let’s take a look at a few of the different categories of bets you can make.
Here's another way to look at it:  Let's say you bet $10 on every number, one bet on each of the 38 spots.  So you've just thrown down $380 in bets.  Only one of those numbers will win, and will pay 35 to 1, so you'll get back $360 (the $350 you won plus your original $10 bet on that number).  You bet a total of $380 but you walked away with only $360, so you lost $20.  That $20 you lost represents the house edge of 5.26% ($20 lost divided by the $380 that you bet; $20 ÷ $380 = 5.26%).

Over the course of time, casinos decided to improve the house edge and since imagination is not their strong suit, the solution was to add another zero. The betting table changed its structure many times and when the game was imported to America, these changes grew numerous. French Roulette has a more traditional layout and offers better odds for players, while adding two special rules for the connoisseurs.
Go with the Fibonacci System for a low-risk, low-reward strategy. In this system, you place wagers only on the roughly 50/50 bets (such as odd/even), and you base your wagers on the Fibonacci numbers. If you lose in the first round, make your next wager the next number in the Fibonacci sequence in the second round. Keep advancing a number in the sequence until you win then, when you do win, go back 2 numbers in the sequence.[13] 

Those of you have gambled in a casino, even only a few times, have probably stumbled on the Martingale system, even if you didn’t know the word Martingale. You might have even figured you invented it. I know I did. It seems this is the very first concept most gamblers have and it is expressed in the following phrase: “I have to win sooner or later, right?” 
So what were some of the most famous systems used by our ancestors in attempting to beat the wheel? Are any of these still used today when people are learning how to play roulette? I can easily answer both of these questions, with the latter first: Yes! the systems of the past are still used today. Why? Because they are fun to play and structure a player’s game-plan in a way that makes sense to the player. A player always knows what to do next when playing a system. There’s no guesswork in how or what to do next.
No other game on the casino floor gives players the chance of close to 50/50 odds on a single bet. With the red/black, evens/odds, or 1-18/19-36 bets, you’re giving yourself the chance of hitting almost half the options on the Roulette wheel – the 0 and 00 aren’t counted – which gives you a pretty nice chance of winning. Granted, that means that the payout ratio is lower (1:1, bet $10 win $10) but by the numbers, it’s one of the safest and best roulette bets you can go with when playing the wheel.
This third best roulette bet was specifically designed for people who like to hedge their roulette bets, or at least attempt to. The Roulette board is an interesting creature and when studied thoroughly, it may help you score big bucks. On the third column of the board, there are 8 red numbers and 4 black, whereas the second column is reversed, holding 8 black numbers and 4 red.