Why Girl Math Works: TikTok Trend Explained

It reminds me of the last time I got my nails done: I tipped $20 cash and the nails themselves — a bright, fiery red gel manicure — cost $60 that I charged to my credit card. Because I used cash for the tip it was, essentially, free, and because these nails will likely last me three weeks, I’m technically only paying $2.85 a day to have nice, well-groomed nails, which sounds a lot more worth it than a one-time purchase of ~$80. It might sound wrong and maybe even a little absurd, sure, but if you know what I’m talking about then you know. That’s girl math. Frances Solá-Santiago, fashion writer at Refinery29, recently used girl math on an incredible, highly necessary $100 purchase: six bottles of wine. “(Normally) $100 is five glasses at a bar, so five bottles were free,” she explains.