This is a complete calculator made with the new unity UI for Unity 4.6 and Unity 5.
The package comes with complete source code for you to play with.
This calculator accurately replicates the traditional Windows calculator that you would find on your desktop.
You can use it as the basis for your own calculator to sell on the stores. For example you could skin it and add nice button images to it.
You can drop also take the calculator and drop it into your own project. Use it to ask the user for numerical input for example.
Or for a challenge you might like to try converting it to handle complex numbers! Or try adding scientific functions to it.