I'm not familiar with the fraction button. Is this common on calculators? I don't see it on most of the basic function calculators that I look at. Hmm, taking a look around, it looks like it might be present on a lot of scientific calculators, but not the basic calculators I see. I had switched to RPN by the time I started using scientific calculators, so I guess I never became familiar with this button.
Parentheses are common on scientific caclulators and graphing calculators, but as you demonstrate, they add a lot of extra button presses, and you even left out the final "=".
To do this on an RPN calculator, you need nothing beyond the basic 4 functions and the enter key, while you need extra specialized keys like parens or a fraction button to do it on an infix calculator. Taking a look at various infix scientific calculators, they mostly seem to have both parens and a fraction key, so using up the space of 3 keys that an RPN calculator doesn't need and can use for more actual functionality.
You wrote it in Polish notation rather than Reverse Polish Notation, and had left out the enter key that is used as the delimiter between two numbers (pushes a number to the stack, so you can start entering the next number).
Parentheses are common on scientific caclulators and graphing calculators, but as you demonstrate, they add a lot of extra button presses, and you even left out the final "=".
To do this on an RPN calculator, you need nothing beyond the basic 4 functions and the enter key, while you need extra specialized keys like parens or a fraction button to do it on an infix calculator. Taking a look at various infix scientific calculators, they mostly seem to have both parens and a fraction key, so using up the space of 3 keys that an RPN calculator doesn't need and can use for more actual functionality.
Here's how you do it on RPN:
3 <enter> 4 + 5 <enter> 6 + / 7 <enter> 8 + 9 <enter> 2 + / +
You wrote it in Polish notation rather than Reverse Polish Notation, and had left out the enter key that is used as the delimiter between two numbers (pushes a number to the stack, so you can start entering the next number).