If it’s less than $5 it’s basically free. If you return an item for a refund, you’ve made money. If you paid for a vacation months ago, it’s free by the time you go on it. And if you buy something using cash you found in your pocket, it’s also free.

That’s the bizarre logic of “girl math,” the latest TikTok trend in which women rationalize their spending in illogical ways. It’s one of dozens of “girl” trends to sweep the internet, but not everyone is laughing this time—some think the trend perpetuates the stereotype that women are irresponsible with their money. What it also seems to show is an emerging attitude, especially among Gen Z and young millennial women embracing the trend, that money is a fabrication, so spending it can always be justified—or, in other words, money isn’t real.

It’s “basically free”

The term “girl math” was popularized in July by a trio of New Zealand radio hosts on ZM’s Fletch, Vaughan & Hayley. In one of their segments, they helped a caller justify $5,600 spent on travel, accommodations, and tickets to all four nights of the Taylor Swift Eras Tour in Sydney. The group reasoned that the purchase was “basically free.” Girl math logic goes like this:

Since the caller is going to all four consecutive shows, she “saved” money by only buying a single round-trip flight. After all, “She’s going to four shows, but she’s not buying eight flights—she’s buying two flights,” one of the hosts, comedian Hayley Sproull, said. “She’s saved $1,800 there.”

Accommodations for four nights in Sydney are justified, too, if the caller can sublet her apartment for those nights. That way she’s not paying for lodging in two different locations simultaneously, they said. The remaining value is eventually canceled out if the caller rewatches the videos she takes at the concert 1,000 times since those are essentially “free” concerts.

Not to mention, being able to tell her children and grandchildren that she saw Taylor Swift live at the iconic, record-breaking Eras Tour is priceless, they concluded.

“My mom always tells me, ‘I saw Freddy Mercury live,’” Sproull said. “You’ll be able to say ‘I saw Taylor Swift in the flesh.’”

“I can’t believe we’ve even bothered justifying this, to be honest. It justified itself,” she added.

“A lifestyle and a delusion”

Girl math is a joke—or is it?

Although girl math videos don’t directly communicate a mentality that money is created out of thin air, the phrase “money isn’t real” appears in many adjacent social media videos. And it’s no coincidence, since Gen Zers and young millennials have grown up watching the Federal Reserve effectively print trillions of dollars as the U.S. continues to sink deeper into debt.

“At one point the dollar was backed by something. It was backed by physical, tangible gold that existed, and now it’s backed by hopes and dreams,” one TikToker said in a video.

Another TikToker said, “With knowledge of the fact that money isn’t real and the economy is all made up, can we all agree that people who studied econ in college basically got theater degrees?”

The concept felt unsatisfactory in 1975, too, when economist John Kenneth Galbraith wrote in his book, Money: Whence It Came, Where It Went, “The process by which banks create money is so simple that the mind is repelled. When something so important is involved, a deeper mystery seems only decent.”

Compound that with these generations’ distrust of large institutions, and voilà, trends like girl math are born. Their cynical, apathetic attitudes towards finance are unsurprising given they’ve lived through financial crises, a pandemic, and under the shadow of climate anxiety. Girl math is less a joke and more a coping mechanism for the twentysomethings who have no savings.

As Shannon Trim, a producer at the New Zealand radio show, joked in a segment: “It’s a lifestyle, and it’s a delusion.”

Financial behaviors “we know we shouldn’t be doing”

Girl math is just the latest in a long line of “girl” trends, from this year’s “girl dinner” and “lazy girl jobs,” to last year’s “hot girl walks” and “hot girl summers,” and the pre-pandemic “VSCO girl.” The hashtag #girlmath has amassed over 45 million views on TikTok. Like its predecessors, this one is relatable to many—and has also brought out the critics.

“‘Girl math’ is just the latest iteration of us trying to rationalize financial behaviors that we know we shouldn’t be doing,” Brad Klontz, a psychologist and financial advisor, told CNBC on August 19.

Haley Sacks, known on social media as “MrsDowJones” and who was featured on Fortune’s 40 Under 40 list in 2020, believes the approach infantilizes women and encourages reckless spending.

“While I get that it’s meant to be funny, stereotypes like this impact behavior. It just solidifies a tired, dangerous narrative,” Sacks wrote in an Instagram post on August 20. “Just another example of how differently men and women are spoken to about money in the media!”

“Men are told to invest and grow wealth, women are told we are dumb and can’t be trusted to secure or manage a bag,” she added. “Even if it’s meant to be funny- this messaging seeps into how we view ourselves. And it’s going viral.”

Contrary to what girl math might suggest, women aren’t the only ones dishing out big bucks. Men are statistically as likely to splurge as women, according to a Deloitte report from April. And when they do, they shell out the most money—almost 40% more globally and in the U.S.

That’s partly because men have more to spend. Despite a recent shift, men still hold most of the money, controlling two-thirds of total U.S. household financial assets in 2020 according to a McKinsey report.

Could men benefit from the carefree approach to girl-math advocates? One Fletch, Vaughan & Hayley viewer seemed to think so, writing on the show’s Facebook page, “Guy math now! I want to justify some car parts.”