HP calculators rock, and the older models are better
the older HP calculators are the way to go - the keyboards are much better than the newer models. I also own a circa 2010 platinum 12C, and the keyboard started having problems within about a year; I've been been using a borrowed 1985 model, and it's still rock solid.
Reverse polish just makes sense (although, in fairness and full disclosure, my first calculator when I was very young was an HP, thanks to my engineer dad). It's how we are taught to solve complex equations - start inside the brackets and move outward. That's how HP calculators work. When I got my degrees, I was consistently faster on exams than all my classmates, who were using the school-recommended TIs and were struggling with whether they had gotten all of their brackets in the correct spots. The "calculator with no equal" is just that - it's a great product.
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