This is a simple java app gives you easy to use calculator with a simple click.
Just download the attached apk (zipped up) and make sure you have Java installed. Then unzip the file and double click to launch. Once the app launches just put in the simple calculation (Addition, Subtraction, Multiplication and Division) that you want to see. Afterwards, just click the 'Clear' button to clear the displayed number or just click the 'Exit' button to exit the app. Note app is not resizable.
Attached apk file tested on Mac OS X and Windows OS PC. Screen Caps shown below taken from Mac OS X.