I did UIL competitions in Texas in the late 90s and early 2000s, including calculator competitions.

That's the only place I've ever heard of RPN, which is what nearly all of the winners used, and which we learned to stand a chance.

I waddled into my first UiL calculator test because the sponsor wanted to get more team members and spent most of my time blown away watching kids entering problems into two calculators simultaneously

When I was in high school in the 1980's, the other students knew RPN only as the reason they couldn't borrow my weird calculator.