The Unity Scope Calculator is a fast and convenient way to do simple math calculations without leaving your desktop. The scope works using GCalctool – the default calculator installed in Ubuntu. Therefore the scope is capable of handling most basic mathematic operators and requests such as ‘+’, ‘-’, ‘%’, ‘sin’, ‘pi’, etc.
To install it open a terminal and type
sudo add-apt-repository ppa:scopes-packagers/ppasudo apt-get updatesudo apt-get install unity-lens-utilities unity-scope-calculator
After installing the scope you will need to log out and back in to make the tool available. To use it, hit the ‘Super’ key and type in your mathematical query. The scope will analyse the sum and present an answer.
I think that it would be better if it didn't show the calculator image and the result had a bigger font. Moreover it would be useful if clicking on the result copied it from Dash to clipboard. However it is a nice lens.