It’s actually misandrist because girl math is actual math. Originally it had to do with how a person earmarked money spent and not spending it and deciding to spend it on something else and considering that to cost zero. But that works out economically as that money was already spent and it is, in fact, how economists consider spending. So as it turns out, “girl math” is just conventional economics and “guy math” is wrong as guys are effectively emotionally “spending” the money twice.
It’s actually misandrist because girl math is actual math. Originally it had to do with how a person earmarked money spent and not spending it and deciding to spend it on something else and considering that to cost zero. But that works out economically as that money was already spent and it is, in fact, how economists consider spending. So as it turns out, “girl math” is just conventional economics and “guy math” is wrong as guys are effectively emotionally “spending” the money twice.