School quality in the US is very location dependent, as public schools are largely funded by property taxes. I also went to a public east coast high school, and calculator use was mixed. Some exams allowed calculators, others not. Often the exam was designed such that it was testing your knowledge of a concept more than the numerically correct answer, showing work was required. So a calculator was useful for checking answers but correct answers with no work would get you a 20% at best.