Reverse Polish Notation (RPN) provides a quick to enter data in a calculator because it eliminates the need for parenthesis.This is a simple online RPN calculator for you to try out. It's written in Javascript.
https://ullash21.github.io/RPN-Calculator/
Step 1
Open a terminal and type: git clone https://github.com/ullash21/RPN-Calculator in a suitable folder
Step 2
Open index.html file with a borwser
Step 1 Download the code by pressing the code download button on top right of this page
Step 2 Unzip the files in a suitable folder
Step 3
Open index.html file with a borwser