Linda likes number games, but this is a tricky one.

Linda is 81 years old. She lives on roughly $2,000 a month. Every day her postal carrier brings her 50 to 120 invitations to enter sweepstakes or solve puzzles for cash prizes. Linda believes she can win these contests, and so she pays the entry fees, anywhere from $5 to $40 each. In five days last month Linda wrote 40 checks to contest companies, $594.39 in all. She also bounced 23 checks in March and was charged $35 for each overdraft. When Linda’s daughter checked her mom’s bank account, she discovered Linda had spent $10,000 from February to March. Linda now has 2 cents in savings.

The odds of solving this problem are as good as Linda’s chances at winning any of the many direct mail contests she has paid to play. She is one of many consumers, according to the Federal Trade Commission, who are “deceptively lured into playing skill contests by easy initial questions or puzzles,” becoming hooked and, as the questions get harder and the entry fees higher, “rarely receive anything for their money and effort.”

Junk mail contests and sweepstakes are perfectly legal in Nevada and most states, provided the odds are disclosed to entrants. Of course, disclosure can look like a lot of things: Like a little slip of small print tucked into a crammed envelope, or a paragraph printed on the back of a paper promising BIG WINS. These halfhearted disclosures make the contests perfectly legal and perfectly manipulative, at least according to consumer advocates, who argue that the schemes fool the elderly, uneducated and naive into thinking they’ve struck it rich.

Linda — who’s fuzzy when it comes to remembering things like her ZIP code, how long she has lived in Henderson, how much money she has spent on contests — doesn’t read the fine print. She’s focused on the envelopes that land in her mailbox, covered in neon stickers or stamped with phrases like “restricted information for addressee only,” “attention at once — financial disclosure,” “account alert — return important enclosures at once” — all in eye-grabbing capital letters.

Inside the envelopes, more direct mail double-talk, the text version of a late-night infomercial: “You are holding real documents sent to you from the AWARD NOTIFICATION COMMISSION ...” Send in a number, solve a little puzzle, sign a document — always enclosing a payment for “confirmation processing” or a “registration fee” or a “release fee.”

You could win so much money, one letter said, “you may wish to consult a financial professional for investment purposes.”

The FBI estimates consumers lose hundreds of millions of dollars every year to mass marketing schemes like these, Supervisory Special Agent Jason Pack said. More than 50 million people play junk mail sweepstakes and contests every year — and millions play more than once, reports say. In one contest mailing Linda received, the fine print revealed 100,000 entrants were expected to pay $5 to qualify for round one of a multi-round competition. Another contest disclosed its odds to win were 1 in 300 million.

The sweepstakes and contest companies are accustomed to criticism. In 2002 the attorneys general of 10 states joined to go after Contest America Publishers, a Kansas City, Mo., company that’s been in business for more than 30 years. Without admitting guilt, the company agreed to issue several thousands of dollars in refunds.

On Thursday, Contest America customer service representative Erika Barrett said entrants who do not understand the contests can ask for refunds by calling the phone number listed on all contest mailings. Besides, she said, “there are people who are going to win, and there are people who are going to lose.”

And that, after all, is the same maxim accepted by Las Vegas’ millions of casino gamblers.

Barrett said Contest America does not know the ages of the people it sends its contests to. So to suggest that the company specifically targets the elderly would be misleading, she said.

Even if the company is not specifically targeting the elderly, Yale professor Ravi Dhar said, it is taking advantage of them. Many of the contest mailings are designed to look official, with seals that emulate government documents or financial papers. Many are also personalized, with type designed to look like handwriting. Some elderly people aren’t aware this is possible with modern printers, said Dhar, a marketing professor who has studied the sweepstakes business.

Susceptible people, the same people who tend to play the lottery and other hard-to-win games of chance — are more likely to focus on the possible payoff than the probabilities, he said. The contests seem even more plausible than sweepstakes because they are presented as games of skill rather than games of chance, he said. And disclosing the odds is not enough, Dhar said, if the odds aren’t clear.

“Even if they’re prominent, they can still be misleading.”

Some media accounts have suggested many direct mail scams operate out of Las Vegas, but none of the mailings Linda received appeared local. Edie Cartwright, spokeswoman for the attorney general’s office, said there are no cases currently pending against bad operators, and she was unaware of previous litigation.

But the Nevada attorney general’s consumer protection bureau does receive a few complaints or inquiries about mail sweepstakes every week, most of which come from senior citizens, Senior Deputy Attorney General John McGlamery said. Nevada’s Fight Fraud Taskforce, a division of the Business and Industry Department, has a Web site specifically aimed at seniors — fightfraud.nv.gov/Seniors.htm — who are at risk because they tend to have savings stored up and are trusting, said Elisabeth Shurtleff, the task force’s chairwoman.

Linda, who asked that her real name not be used, said she now understands that she wasn’t a winner. What she doesn’t understand is how strange companies are now directly withdrawing money from her bank account.

Inside many of the contest mailings Linda receives is a form that allows for payment by credit card — just fill out your account numbers and sign. Linda swears she never did that.

She did, however, accept a number of phone calls from strangers across the country who reported that she had won large amounts of money. If Linda would wire them transfer fees and taxes, the money would be hers. In the past few weeks she started wiring money around the globe: New York, Florida, Costa Rica, Utah and Mexico, roughly $2,000 in all.

Bulk mail companies sell the addresses they collect to other bulk mail companies. This is the beginning of a circle: The more games you play, the more your address is distributed, the more games show up at your door. Suddenly your mailbox is overflowing and you’re getting five calls a day from strangers wanting money.

Last Wednesday, Linda accepted such a call. The person on the other end of the line, speaking over a bad connection, explained that Linda had won a large sum of money, and needed to wire a $300 collection fee to New York. When Linda started taking down directions from the caller, an onlooker took the phone from her hand and asked the person on the line what they were after. The phone went dead and Linda looked listless.

“But they have money waiting for me,” she said. “They had it right there.”