RPN is also consistent in its usage. Most non-RPN scientific calculators are half RPN and half algebraic. For example, to perform addition, you need to enter 2+4 (algebraic), but to perform a sine calculation, you need first to enter the number and then to press the SIN button, which is a RPN method of entering the equation. Our RPN calculators do not suffer from this idiosyncrasy.
Here's an example:
3+57+6
Or (3+5) / (7+6) = x
Algebraic method: Add 3+5=8. Write down the answer or store it in memory. Add 7+6=13. Now enter the 8 from the first answer and then divide it by entering the second answer to get x=0.62.
RPN method: Press 3 then the ENTER key. Press 5 then the + key. Press 7, and then ENTER. Press 6 then the + key. Note that the answer to the second sum is displayed. Now here's the magic part. Press the divide key and the calculator gives the answer, 0.62.
Algebraic: 13 strokes, not counting the effort to write down or memorize the first answer while you calculated the second answer.
RPN: 9 strokes, and no need to write anything down.