They didn't patent math. They survive for a few reasons: - Standardized testing calculator requirements are crafted in such a way that graphing calculators are

They didn't patent math. They survive for a few reasons: - Standardized testing calculator requirements are crafted in such a way that graphing calculators are allowed by specific model: https://apstudents.collegeboard.org/exam-policies-guidelines/calculator-policies https://apstudents.collegeboard.org/exam-policies-guidelines... - Textbooks contain instructions on using TI calculators (and sometimes, if you're very lucky, Casio). Teachers can only provide personal instruction with TI because that's what the schools buy (presumably thanks to marketing and dealmaking). Math classes are already hard for high schoolers. Having to deal with the disadvantage of being on a different platform from your peers is hard.