How much is being wagered, the initial stake (in money or material goods).

The predictability of the event.

In mechanical or electronic gambling such as lotteries, slot machines and bingo, the results are random and unpredictable; no amount of skill or knowledge (assuming machinery is functioning as intended) can give an advantage in predictability to anyone.

However, for sports events such as horse racing and soccer matches there is some predictability to the outcome; thus a person with greater knowledge and/or skill will have an advantage over others.

The odds agreed between the two (or more) parties to the wager; where there is a house or a bookmaker, the odds are (quite legally) arranged in favor of the house.

The expected value, positive or negative, is a mathematical calculation using these three variables. The amount wagered determines the scale of an individual wager (bet); the odds and the amount wagered determine the payout if successful; the predictability determines the frequency of success. Finally the frequency of success times the payout minus the amount wagered equals the "expected value" The skill of a gambler lies in understanding and maneuvering the three variables so that the "actual value" is positive over a series of wagers.

While almost any game can be played for money, and any game typically played for money can also be played just for fun, some games are generally offered in a casino setting.

Gambling is different in two respects.
First, the satisfaction sought by the gambler is, strictly speaking, measured in terms of money. The gambler might enjoy the activity of gambling but his/hers central objective is to make money. Secondly, the price paid for the gambling experience is not a fixed price but is variable. The gambler is placing his/hers money in a chance ebb and flow environment where he/she will win or lose-or, perhaps, break even. The gambler may well come away with more money than he/she outlaid in short sessions of gambling.As we have seen gambling, the price is variable. Variability is, itself, most important. The variable cost of gambling is one reason why a gambler should only gamble with "play money", money that is of no consequence to him/her (or their families) if he/she loses it.
Money management is important to the gambler as it allows you to last longer at the tables and become a very disciplined and tough player. Gambling using Money management techniques is a valuable way to enjoy your casino visits, and maximize your wins and minimize your losses.Don't forget that an important part of money management is cutting your costs for playing.
Remember Double Up and Catch Up is a Loser's Epitah, Skill and Odds Cannot be Beat.Good Luck.