This isn't true for all countries. I did my high school in India and I had to do tax returns (ex. calculate taxes for a working couple w/ mortgage, investment income, PF (401k) etc.) and financial calculations (compound interest etc.) as part of math class. I think it was in 10th grade ?? Don't know. This is the baseline. Certain streams in high school had full blown booking keeping courses, accounting practices and…
To clarify - do you mean Indian equivalent of 401k or did they have you do American income taxes in an Indian school? (Were that many folks planning to go to US??)
India also had other tax deductible stuff like infrastructure bonds etc.