Girl math

The phrase girl math is an internet meme, used to describe rationalizations by young women to justify indulgent and potentially irresponsible spending habits. Originating from and appearing on the social media platform TikTok, later transferring over to Instagram and X (formerly known as Twitter).

History
According to KnowYourMeme, the origins of this trend stem from the TikTok user's @samjamessssss video, in which she encouraged the transition from “Girl Dinner”, another popular TikTok trend amongst women, to girl math. Girl math echoes the “women be shopping” meme, in which men satirised the excessive purchasing habits of women. However, in the case of Girl Math, it was created and popularized by women themselves on TikTok.

Another possible origin of the trend is thought to be from a New Zealand radio show “Fletch, Vaughan & Hailey”, where they have a segment called girl maths. The idea for the segment occurred off-air, where their social media producer helped one of the producers justify getting their hair done for an expensive price. For this segment listeners would call in and share their big-time purchase, and with the help of the hosts they would help them justify spending the money on the item. The methods of justifying would range from using the means of cost-per-use/cost-per-wear, to breaking down credit card charge. The original segment became especially popular once it got to TikTok, where the trend went viral.

Psychological background
Several psychological concepts are relevant to girl math, including cognitive dissonance, confirmation bias, the framing effect, and mental accounting theory. Cognitive dissonance is when someone experiences mental tension which arises from holding two contradicting beliefs. Girl math is applied to alleviate said mental tension through the usage of biases and heuristics. There are multiple biases used in girl math one of them is the confirmation bias, where people choose to pay attention to evidence that supports their decision and ignore what does not. The framing effect is another bias, which allows people to make inferior choices based on positive nuance.

Mental accounting theory helps form the basis for girl math. The main premise of it is the organization of money into different "mental buckets", such as one mental bucket for paying rent and one mental bucket for going shopping. This affects how one perceives financial gains and losses in relative instead of absolute terms. If people find money on the sidewalk or get their tax refund, it makes them happy because the money has not been organized into a mental bucket yet and is therefore considered free money which can be spent however they want.

Effect of gender stereotypes
The rise of online trends on social media platforms such as X and TikTok, that pertain to the concept of “girl math” and “boy math” could potentially be influenced by and influence gender perceptions, as proposed by some research. Gender perceptions are the cultural and social views of males and females. There is a difference in the meaning behind the trends because when “girl math” is referred to it most commonly celebrates femininity with positive appraisement amongst women. Women tend to use the trend in a more humorous way to shine a light on how women spend their money and make decisions, which then ultimately transformed into a broader trend that addresses various issues related to womanhood.

There has been some backlash as people find that it perpetuates the notion that women's thought processes are irrational. Researchers have proposed that girls may adopt these societal preconceptions of boys being superior in academic subjects including math, which can result in heuristic linkages leading to underperformance in mathematical tasks. This has been demonstrated in studies, where girls who were primed with negative gender stereotypes regarding math, showed worse performance in mathematical exams, in contrast to those not being primed. Studies on stereotype threat in the field of mathematics also show that when women are influenced by stereotype threat, they tend to express more negative thoughts regarding the domain of mathematics. With some male users reportedly disregarding the trend as “delusional” and using it to support the stereotype that women are not mathematically capable, the negative feedback gained from girl math led to the emergence of “boy math”.

“Boy math” on the other hand does not address how they spend money, but rather addresses male behaviour, especially in romantic and sexual relationships, aiming to highlight instances of misogyny and toxic masculinity. The subsequent trend shows women weaponizing language in order to shame men for behaviours that harm women, rather than outwardly censuring the male population. “Boy math” has a certain negative connotation to it, because often the language used to criticize the toxic masculinity and misogynistic behaviours people have witnessed, is negative.

Behavioural economics
For many the trend of girl math is seen with the purpose of bring women together during times of economic challenges. For participants, it serves as a reminder that it is valid to put yourself first sometimes and it is valid to satisfy this craving of a sense of ease and comfort found in non-essential purchases. Spending money is seen as a form of self-care and has become a tool for justifying luxury for one’s mental well-being.

The trend of girl math utilizes cognitive biases that are prevalent and commonly known in the economic domain. One of these irrational decisions marks the saying that paying in cash is basically free. This is applicable to the “pain of paying” – the guilt felt when spending real “visual” money. It is common for some people to feel this way as cash is not traceable and allows one to forget about an unjustified purchase because it does change the bank account balance. This “cashless effect” is another frequently encountered bias about people generally being more willing to buy something when physical money is not involved in the transaction. This helps explain the statement that paying with a gift card is free. Another phenomenon promoted in the girl math trend is “cost-per-use”, which refers to justifying expensive purchases by dividing the sum across the days of usage.

Criticism
In a widely spread TikTok video, Marley Brown, a college freshman, attempted to explain the girl math concept to her concerned father. She jokingly said that if she bought concert tickets for two and was reimbursed, the repaid money felt like "free money" since her bank account had already been charged. Thousands of comments, primarily from women, resonated with Brown's logic, revealing that they also apply girl math principles to their everyday purchases. However, financial experts warn against viewing certain expenses as "free". They emphasize that rationalizing small purchases can hinder long-term financial planning, by pointing out, for example, a daily $5 coffee, which can be very easily "girl math-ed", may seem insignificant but can accumulate to $100 a month or $1,200 annually.

A more serious criticism comes from the idea that by labelling illogical calculations as girl math, this trend trivializes women's mathematical abilities and highlights the stereotype that women are inherently less skilled in logical reasoning. The implications of girl math extend beyond individual perceptions, reinforcing historical biases that have historically marginalized women in mathematics and related disciplines.

For girl math's proponents, the trend is light-hearted fun and it should not be taken seriously. Girl math is no longer considered to be fun when one earnestly uses it to justify their bad spending habits and alleviate any sense of guilt. In some cases, girl math can undermine the significance of small expenses made on a daily basis. If the long-term consequences of small daily expenses are not factored into one’s finances, then financial trouble is a likely consequence in the future, especially if the tenet ‘5 dollars is free’ is taken too seriously.

Despite the multi-faceted criticism, most participating women understand that their purchases are something they want rather than need and are still capable of rational budgeting, making these purchases possible.