Drag the tile into your quick settings from the customization menu.
Touch the tile to start the floating calculator, you can move it on your screen.
The calculator can be used to perform simple mathematical operations such as additions, subtractions, multiplications and divisions, without having to juggle with other applications.
You can also find a button that will launch the Calculator application on your smartphone if you need to perform more advanced operations.
For More Info Google Play
Supported Android
varies with device
Download Calculator Quick Settings Tile 1.4 APK For Android