> they introduce variables in 2nd grade
you are not familiar with public education here. In one coastal city, more than 40 languages are spoken by students at home, with Spanish being a large component.
What I am saying is that 9th grade through 12th grade public standard curriculum is the topic of debate, with some groups, today, advocating removal of "advanced placement' courses in a broad way.
There is massive difference between certain particular schools, and the broad standardized, State-assigned curriculum.
Seattle? SF? Schools They are just suck but even adjacent functional districts don’t teach like that. The educational and conceptual math philosophy is simply different. Variables are really interesting at elementary school age because they really flush out when a student doesn’t understand the concept and allows the teacher or parent to correct it early. Numbers sometimes mask what’s going on and let students take shortcuts that hurt them later