Girl math, a term that describes the unique ways girls justify their spending habits, has taken the internet by storm. In a new video on TikTok, a girl tries to explain to her dad what the term actually means.

Marley Brown (@thebobmarleyy) posted her four-part video series on TikTok explaining the cultural phenomenon to her father. In the first video, she says, “If I buy concert tickets for two people and those people pay me back, the money they pay me back is free.” She says that since the money had already left her account, the money she then gets from her friends is considered “free” since it had already said goodbye to her.

Her father immediately shakes his head in reluctance and says she’s simply spending the money twice. Brown then says that by that logic, returning an item and getting the money back also makes the returned money “free money.”

In each video in the series, Brown went through a list of rules. The third video was a huge hit with many, garnering over 11 million views. In the video, she says, “If something is less than $5, it’s free,” before her father responds, “No. What if you buy a hundred things that cost $4?”

“They’re all free,” Brown replies, to which her father quickly says, “No. It’s $400, which is obviously not free.” Brown explains that using money in her Starbucks app to purchase a drink, which customers can do by transferring money from their bank account to the Starbucks app, means it is, in fact, a free drink. “If I want to go to Starbucks and there’s already money in the account, money in the app, it’s free,” she says.

Her father then points out that she has already loaned them money. She then explains that these rules apply to online purchases as well, adding that if a company offers free shipping on items over $10, it makes sense to purchase additional items to qualify for free shipping.

“If the shipping is $4, I should spend the $10 because it’s a better investment,” Brown tells her father, to which his father simply says, “No.”

Many took to the video to talk about the conversation. “Yes, once the money leaves my bank, it no longer exists,” writes one user, while another writes: “Yeeeeah, because I buy these tickets expecting to never see the money again. I know I can count on my friends.”

We’ve all come up with creative justifications for unnecessary purchases, but this particular trend is relatively new. While it may seem amusing, it’s more of a financial joke than a serious budgeting strategy. If you have trouble budgeting, it’s best to avoid this trend.

For more videos like this, follow (@marleyvbrown) on TikTok.