We usually use the Dash to quickly search and access files, folders, and installed applications. It can be enhanced by adding extra lenses. Here Unity Scope Calculator is the scope for Unity utilities lens, it allows you to do mathematical calculations directly in the Unity Dash.

It sends mathematical operations to Gnome Calculator, then display the result in the Dash.

Unity Scope Calculator uses numerous mathematic operators such as “-”, “+”, “*”, “/”, “%”, “sin”, “cos”, “tan”, etc.
To use it, just press Windows Super key to launch the Dash and type a mathematical operation in the Home view and it displays the result instantly.

Get Unity Utilities lens from ppa:scopes-packagers/ppa (so far it supports Ubuntu Oneiric and Precise) by running following commands in a terminal window:

sudo add-apt-repository ppa:scopes-packagers/ppa
sudo apt-get update
sudo apt-get install unity-lens-utilities unity-scope-calculator

Log out and back in.