Following the hyper popular #girldinner trend, #girlMath is a trend in which women depict how they are spending their money, including how they justify and rationalize buying items (whether on sale or not on sale) and consider cost-per-wear metrics ahead of purchases.

One example reads “if your shopping haul was all deals, does it even count as real money?” from discount retail chain Five Below.

The #girlmath hashtag currently has more than 155 million views on TikTok. Many of the videos have been posts made by influencers and everyday consumers. And brands, recognizing the opportunity, have begun to jump in. Marketers such as Babylist, the baby registry brand, Ulta Beauty and Rihanna’s Fenty Beauty are among those doing girl math. Ulta used #girlmath to promote its loyalty program as a way of driving down costs for customers.

The #girldinner trend saw women post random and effortless dinners, usually light and smaller than a male portion, from yogurt and crackers to crisps and apple slices with peanut butter. In this case, #girldinner seems to reflect a lack of responsibility. The same goes for Girl Math; “if you buy a coffee for you and your friend and she buys a second round it is technically free” showcases a lack of economical fluency. Is Girl Math sexist? Well, it all depends on the video using the hashtag, requiring the treading of a fine line. 

For this reason, marketers need to get it right. The danger lies in offending customers by falling into a sexist trap that condescends to tell women they are bad at math. According to Cindy Gallop, a gender equality advocate, consultant and CEO of IfWeRanTheWorld, the way to do this is to be “original, creative and empathetic,” and acknowledge that #girlmath is a joke.

“The fatal thing for a brand to do would be to take this literally and talk down to consumers,” she wrote in an email. “I see too many brands fail to respect consumers, especially when those consumers are female.”