Guess I do not understand, what does a “math program” have to do with how you use a calculator to solve an equation or calculate something?
I thought as you did until I became aware of the manner in which the advanced math teachers instruct the students every day in class. They “teach to” the TI product (TI n-spire CX or TI n-spire CX CAS) that every student possesses and has possessed for decades now. A student whose parent bucks the trend and bought them an HP calculator (with an entirely different keyboard, different menu system, different functional breakouts, and of course a legacy of supporting Reverse Polish Notation that TI has never troubled itself with) quickly finds himself or herself at a distinct disadvantage. The instructional methods and study materials used by more or less every advanced math teacher in this country are so completely married to the specific functional breakouts, dropdown menus and overall logic that are unique and particular to the top-of-the-line TI calculators mentioned above, that they have effectively enshrined them in the class curriculum and handed near total monopoly market control over to Texas Instruments. Hewlett Packard’s RPN-supporting top-of-the-line calculators, fine and magnificent though they may be, occupy the ghetto of the high school and college/university advanced math market. HP’s overall market share in high-end personal calculators compared to TI’s is now an embarrassment. Unbelievably puny.