Rise of 'girl math' and 'boy math': Gen-Z shoppers think using cash doesn't ... trends now

The new phenomena of 'girl' and 'boy' math is taking TikTok by storm as Gen Z shoppers bizarrely claim using cash doesn't count as spending money and anything under $5 is effectively free. 

Consumers are sharing their often illogical justifications for making purchasing under the hashtags. In dozens of videos, people find ways to convince themselves they have either saved or even made money while buying things.

TikTok user McKenna explained the rules of 'girl math' simply as: 'Anything under $5 is free, anything I buy with a gift card is free.'

'If I buy something but then I return it, I made money. Going to an event or concert is free because I purchased the tickets so long ago it doesn't even count.'

'Girl math' helps women justify purchases they made and often looks at ways consumers can convince themselves they have saved money. 

 '[If I] return something at Zara for $50 [and] bought something else for $100, it only cost me $50,' said Samantha Jane, 28, in a TikTok.

In an interview Samantha Jane said, 'Girl math is fun logic. We can justify things however we want to in our heads — we can make our own rules. It reframes the narrative and takes away the shame around spending money.'

User Asia Jackson posted the 'girl math' explanation for making money.

'If I put $25 in the pocket of my jacket and I forget about it, and then months later I put my jacket on and I find $25 in my pocket, I've made money.'

On the flip side, 'boy math' takes a more frugal approach to purchases compared to 'girl math's' splurges.

TikToker Mads Mitch explained, 'boy math is not wasting your money on frivolous things. It's [about] being economical, it's being thrifty.'

Mads claimed that men will often round up their height in a bid to attract female attention, and poked fun at their use of 7 in 1 shampoo.