Examples in Calculator you can find on PC. In mobile - only calculate! And if you want something special, what you can't calculate, tell about it! We will talk about it more closer ;3
Don't forget about references and your idea, or give me full freedom! Live your PayPal email (later we add window for that) and don't forget to check spam in your mail box a bit later. Cuz my mail-reply sometimes send it in this folder.
