Understand the math that makes most bettors lose and bets profit.

This percentage that returns to bettors is called, in jargon, return to player (RTP). Although 93% seems like a high number, it's not good news, because it actually means paying an implicit fee of 7%, if the figures released by the employers' association IBJR (Brazilian Institute of Responsible Gaming) are adopted. According to the Central Bank's analysis, the RTP is 85%, which raises this share for companies to 15%, reveals a report by Folha de S.Paulo.

Therefore, if bettors continue to wager whatever they receive as a prize, the tendency is for the house to take a share of the pie in each round. Since this is a statistical projection, changes are possible, but the betting business model thrives because it usually gets the numbers right, according to statisticians consulted by Folha de S.Paulo.

The law of large numbers favors the bets.

Statistics are also on the side of the house. Individual gamblers don't have enough money to gamble indefinitely. "When they lose everything, it's over," summarizes Marcelo Viana, director-general of IMPA (Institute of Pure and Applied Mathematics) and columnist for Folha.

"As for bettors, they can expect the number of bets to rise," he says. The more games there are, the closer the results will get to the estimated average of 93%. This is a fundamental principle of statistics, the law of large numbers.

An example of this property is the chance of getting heads and tails on a fair coin. In ten tosses, the proportions are unlikely to be balanced—there will probably be more heads than tails, or vice versa. But if a person tosses a thousand times, they will see that the proportion of heads will approach the proportion of tails, reaching a 50/50 situation, as indicated by the average.

The IBJR (Brazilian Institute of Gambling and Sports) clarifies that betting is "an entertainment activity, where the objective is to have fun, with the possibility of making winnings by paying for a ticket." It is up to the player to exercise moderation.

The possibility of winnings, although a minority, is also guaranteed by mathematics. "Betting is a random event, you can't know what's going to happen," says Viana.

Betting profits come from calculating the odds.

But a betting company doesn't calculate winnings based on the probabilities of actual events. These companies adjust the factors to guarantee revenue.

“In an online bet, the calculation isn't based on a random event, like heads or tails,” says Alexsandro Bezerra Cavalcanti, a statistics professor at UFCG (Federal University of Campina Grande). In a coin toss, the odds are 50% or 50%.

In betting with an intermediary, the bookmaker earns its revenue by calculating bettors' winnings based on an "exaggerated" probability of each event occurring.

It works like this: suppose that, in the case of a game between team A and team B, the estimated probabilities are 20% for a team A victory, 30% for a draw, and 50% for a team B victory. In this case, someone betting on team A could expect to receive 5 times their stake (i.e., 1/20%), someone betting on a draw could expect 3,3 times their stake (1/30%), and someone betting on team B would expect 2 times their stake (1/50%).

However, betting sites offer smaller multipliers to their bettors, which results in a lower profit margin.

The sum of the probabilities, then, is 108,9%, and the margin was 8,9%.

IBJR's technical director, Angelo Alberoni, says that the odds are provided by specialized companies, such as BetRadar and Genius Sports. "In addition to statistical data, external factors are also considered, such as whether a team will play with a reserve squad or if it will rain during the match."

Cavalcanti, from UFCG, says that the only way for a bettor to win consistently is to build a statistical model superior to that of the bookmakers. "The player needs to understand their chances of winning and losing better than the bookmaker, and their only advantage is needing to collect information on fewer games at the same time."

He, who has already supervised research on the subject, acknowledges, however, that it is a challenge for very few players. "That's why the betting houses profit." Cavalcanti also says that it is common for betting houses to block bettors who win consistently, alleging suspicious behavior.

Developers of online betting and gaming platforms generally have programs to attract mathematical talent to their staff.

The disadvantage is greater in online slot machines.

Regarding online slot machines, such as the "tiger game," the user is already at a disadvantage, says the professor from UFCG. Since there is no external factor, the user has no way to estimate their chances. "The person puts everything in God's hands," he says.

However, luck, thanks to RTP, has been on the banks' side from the start. "It's not exactly biased because the websites are transparent, but it's the rule of the game," says Viana, from Impa.

In the case of the certified, scam-free version of Fortune Tiger, better known as the tiger game, the RTP, according to developer PG Soft, is 96,81% — meaning the rate is around 3,89%.

The maximum prize, called the "jackpot," is 2.500 times the winnings, but the chance of winning it is one in millions of games. Because slot machines have many paying combinations, the simple inversion logic seen in sports betting doesn't work in these games.

The manufacturer of the little tiger game has not yet released the prize table—this information will have to be made public for the game to comply with the regulations of the Ministry of Finance starting in 2025.

The logic, however, is the same as in sports betting: when the prize increases, the risk also increases.

Cognitive biases harm gamblers.

A study by the University of Alberta in Canada, conducted with a sample of 630 students divided into a test group and a control group, showed that people tend to choose the riskier games.

“This happens because of the cognitive bias of magnitude,” says the author of the research and professor of psychology Marcia Spetch. According to this concept, people tend to underestimate the importance of small accumulated expenses and overvalue significant gains.

“People remember more when they win,” Viana summarizes. “The betting market involves more psychology than mathematics.”

If you're looking for fair opportunities, check out the best online sports betting options.