Expert Guide

“Girl Math” With Danica McKellar

Published: Jan 12, 2026
Written by Editorial Team
5 min read

Wondering what the TikTok phenomenon “girl math” is? Danica Mckellar, author of “Math Doesn’t Suck,” breaks it all down.


Have you heard of “girl math”? Perhaps it’s best described in this scenario: You go to your favorite store (say, Nordstrom Rack), find a pair of pants that you absolutely love, but then a few days later when you try them on at home, you realize that they’re just not your jam… so you go back and return them. 

So, why, praytell, does it then feel like you’re actually MAKING money when that $50 gets returned to you?? 

On TikTok, this phenomenon is called “girl math,” and this week we’re breaking it all down on the HerMoney Podcast with someone many people would call the ultimate “math girl,” if you will — Danica McKellar. You may know her best as Winnie Cooper from Wonder Years, but she’s also an internationally recognized mathematician and author of the New York Times bestselling book for middle schoolers “Math Doesn’t Suck.” In other words, she has the singularly unique title of being the woman who helped make math fun — cool, even! — for a new generation. 

McKellar, who is also co-author of a ground-breaking mathematical physics theorem, helps us define the girl math trend and tells us what’s really going on beneath the surface. 

And, yes, she also dishes some juicy details on her life as an actor — she has a new movie coming out soon, “Swing Into Romance,” which premieres October 7th on Great American Family, and we can’t wait to check it out.