Application presents conversion arithmetic statements to polish notation and reverse polish notation. As a sample of usage, application contains simple calculator. Example polish notation is conversion from "7 / (2 3)" to "/ 7 + 2 3", reverse polish notation is from "(2 +3) * 5" to "2 3 + 5 *". The project is located at https://github.com/wtopolski/PolishNotation.