FSharCalc.exe "2 + 2 * (15 / 5) - 2"
FSharCalc.exe "(123 + 321 / 23) - 2"
etc.
Internally it uses FParsec to parse input string and identify numbers and operators.
Infix notation is then translated to Revers Polish Notation using Dijkstra's Shunting-yard algorithm.
Created RPN stack is then evaluated to retrieve the final result.
Unit tests included :)