A shuffle through the Gaming mailbag:

Q. I donâ€™t see why it is inevitable for a roulette combination to lose money when it wins more often than it loses.

If you bet enough different numbers, whether corners, red/black, columns or whatever so that you have 80 percent of the numbers covered, you have an 80 percent chance of winning.

Youâ€™ve stressed that every wheel spin is an independent trial, and past results donâ€™t influence the outcome. So your chance of winning is 80 percent on every spin.

Thereâ€™s nothing that says I have to lose if I have an 80 percent chance of winning every time.

A. Individual players can have long winning streaks with combinations that win as much as 80 percent of the time.

Individual players also can lose on the first or second time they bet such a combination and be playing from behind at the start. They can lose two or three times in a row, and when youâ€™re betting enough to cover 80 percent of the numbers, it takes a lot of wins to recover from that.

Keep in mind that casinos are perfectly happy to have you bet such combinations. They will not ban any combination bettors.

Thatâ€™s because casinos know that if youâ€™re covering 80 percent of the numbers, the odds of the game will push your system toward losses on 20 percent of spins. You lose multiple bets with every loss, some of your bets lose even on winning spins, and you lose more money on the 20 percent that are losers than on the 80 percent that are winners.

Before you start a sequence, a combination covering 80 percent of numbers has an 80 percent chance of winning once before a loss, dropping to 64 percent for twice, 51 percent for three in a row, 41 for four and 33 for five.

If youâ€™ve already won once, you have an 80 percent chance of winning a second; if youâ€™ve won twice, you have an 80 percent chance of winning a third and so on. Winning streaks are frequent, but single losses outweigh at least four wins, and maybe more, depending on combination specifics.

Q. Do slot machines still pay more at higher coin denominations, or has that all been jumbled up now that bets can be so high even on pennies? What about video poker? Do dollar games pay more than quarter games?

A. Overall, slots still pay more on higher coin denominations, though there is room for variation. Dollar slots pay more than quarter slots, which pay more than nickel slots, which pay more than penny slots.

Casinos that really want to market to penny players might have penny games that pay more than nickels or even quarters. Some relatively scarce coin denominations are highly volatile because of low wagering totals. A casinoâ€™s \$5 slots might pay less than pennies one month and be close to 100 percent the next.

But for the most part, higher denominations bring higher payback percentages.

Thatâ€™s not necessarily the case at video poker, where pay tables determine the theoretical payback percentages, and player skill plays a role.

Given optimal play, 9-6 Double Double Bonus Poker will pay the same 98.98 percent regardless of whether the coin denomination is nickels, quarters, dollars or any other amount. Lower pay tables will bring lower returns at any denomination.

Iâ€™ve been in a number of casinos that placed their best pay tables on quarter machines and used reduced pays on dollars. Itâ€™s up to players to check out the pay tables to find the best games, while also making sure not to overbet their bankrolls.