This is the pro version of the app, which comes with additional advanced function and additional dark theming for the app and its widget. You can use the free of charge basic version, however it is not as feature rich as the pro one: play.google.com/store/apps/details?id=com.numix.calculator
CALCULATE WITH STYLE
Numix Calculator is a calculator app design with simplicity and beauty in mind. It follows Google's new material design paradigm.
Swipe from the left and right to get advanced functions panes or use the three dots button below the sliders in the top left of the input box to do the same. Use the buttons on the left of the input box to open advanced functions panes and preferences.
The calculator support all the basic functions (+, -, * and /), but it also has advanced panes that allows thing like trigonometric functions and more advanced functions.
The app also comes with a simple widget you can add to your homescreen that supports all the basic functions (+, -, * and /).
Numix Calculator's source code is available on GitHub: github.com/numixproject/com.numix.calculator
Numix Calculator is fully material designed and as such it is integrated in Android 5.0. If you're on Lollipop you will get all the material design goodness including ripples effects and material UI elements.