Casio fx-9750GIII vs. HP35s - Professional Use

[nickapos]

There is a difference between scientific calculations that require formulas, and basic number crunching you would usually do manually or with a basic calculator.
In this second case the professionals use adding machines even today and adding machines use postfix notation.
I find my Rpn/rpl calculators a lot easier to use in these cases compared to regular textbook scientific ones, but then again, unless you have been an accountant or a bank cashier as I have been many years ago you can survive with a phone calculator app just fine.