Tax forms change. And some little shit complaining "why do we have to learn percentages? Teach us something useful like how to do our taxes." would make for a better joke. And it would be more accurate.
I have never heard of an economy class in high school. And our math teacher did a tiny thing on compound interest in general when we finished a quiz early.
So I don't know what school you went to but it wasn't the normal one.
I hear so many weird ass things from people in the US. Plenty of "why were we taught this and that" as if learning the countries in Europe is somehow some esoteric knowledge. And then I remember having to learn all the countries in the world, all of the US states, all of the capitals for 90% of the countries, all the seas, rivers etc. It's really funny seeing people complain about the tiniest of things they had to learn as if it was med school.