A white woman's confused face with math symbols drawn over it, in four separate images

Girl Math Is the Best Math

It's like Treat Yo' Self but more fiscally responsible.

All over the internet, there has been a trend of celebrating things women do that may seem odd to those not in the know. These are known as “girl” things. (I’m not sure who voted for using “girl” instead of “woman” but that’s what they’ve been dubbed.) We have Girl Dinner, where women eat random food items for meals instead of a more traditional setup. My favorite example of this was two wine glasses filled with mac and cheese with a dinosaur chicken nugget on the rim. A very fancy girl dinner.

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Another fantastic “girl” trend is the phenomenon of Girl Math. Frankly, this kind of logic has been used by women for decades, but this summer it really gained traction online. Traditional math may be what they teach us in school, but Girl Math is something we learn in real life. Just like traditional math, there are solid rules and guidelines. So let’s break down how you can start using Girl Math today!

What is Girl Math?

In a popular TikTok video, user mckennaelianna broke down some rules of Girl Math to prove how it makes sense. Because it totally does.


somehow it makes sense #girlmath ??‍♀️

♬ original sound – kenna ??

Some examples from the video are:

  • Anything less than $5 is free.
  • Anything you buy with a gift card is free.
  • If you buy something and return it, you’ve made money.
  • If you buy tickets to a concert or event months in advance, it is free because that money no longer counts.
  • Anything discounted more than 50% is free and you actually lose money if you don’t buy it.
  • If you planned on buying an item but don’t, you know have that money available to use on another purchase.

Another general rule is anything bought with cash or from an app preloaded with money is free. Listen, I don’t make the rules, I just adhere to them.

I’ll give you a real-world example of Girl Math. A few weeks ago I wanted to buy a new bottle of nail polish but didn’t want to spend $10 on it. Then I noticed the color was “crochet away” and I am a recent crochet convert. So I double-checked my Girl Math with my friend and she confirmed that the nail polish was free. Thank you, Girl Math.

Why do we Girl Math?

I cannot speak for every user of Girl Math, but I think I’ve found a reason women use it. Many times women want to “treat” themselves with coffee, new clothes, or a fun adventure. Yet there is a standard of society that we, especially women, have to “earn” these items. I think this goes double for anyone who grew up in poverty. My parents didn’t have extra income to allow for purchases of non-essential items. Unfortunately, my parents were also awful so even when it was a time when my needs were supposed to be prioritized on birthdays or holidays, they weren’t.

Ever since childhood, I have felt guilty about spending money on myself. No, I don’t really need a new bottle of nail polish, so I probably shouldn’t buy it. Even if I had the extra money, my guilt tells me I should be spending it on something more responsible or saving it. However, with Girl Math, I can justify indulging with some simple steps. Yes, I could just tell myself that it’s okay to buy myself things. I am an adult. But Girl Math is ingrained in my psyche. It’s like Treat Yo’ Self but more fiscally responsible.

(featured image: TV Globo)

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D.R. Medlen
D.R. Medlen (she/her) is a pop culture staff writer at The Mary Sue. After finishing her BA in History, she finally pursued her lifelong dream of being a full-time writer in 2019. She expertly fangirls over Marvel, Star Wars, and historical fantasy novels (the spicier the better). When she's not writing or reading, she lives that hobbit-core life in California with her spouse, offspring, and animal familiars.