The heart of Gambling

Probability is the chance of achieving a particular outcome compared to all possible outcomes.
Casino management and professional gamblers know all about probabilities, and so should you. 

There are only two possible outcomes: heads or tails. Therefore, the probability is 0.5 (one half). The odds are 50-50. The chance is one in two. No matter how you call it, it is important for you to understand what chances you have in a particular game. 

House Advantage

The probability of the event happening can be different from what the casino will pay you. Gambling facilities charge their customers a fee or commission for playing there. This is how they earn their profits. This fee is called edge, house edge, house advantage or more formal vigorish or just vig.
For example, you bet $1. If you lose, the casino gets your dollar. If you win, the casino pays only 99cents to you and keeps 1 cent to make guaranteed profits.
Smart players participate only in games with a small house advantage of course. A reasonable house edge would be 2% or less.

Real Return

How much money do players lose in casinos compared to how much they should lose statistically (by House Edge)? The real amount lost by players is called real return (to the casinos). Here is a table showing how much money a casino should get and how much it really gets out of $100 a player wagers.

Played with $100

This shows only that a lot of players really do not know how to play in a proper way (using perfect strategy).