This is a simple java app that gives you the percentage of a certain number entered.
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 percentage and the number which you wish to know the percentage about. Then click 'Calculate' to get the results. Afterwards, just click the 'Clear' button to put in another entry 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.