The simplest way to see what MEF can do is to build a simple MEF application. In this example, you build a very simple calculator named SimpleCalculator. The goal of SimpleCalculator is to create a console application that accepts basic arithmetic commands, in the form 5+3 or 6-2, and returns the correct answers. MEF component, called a part, declaratively specifies both its dependencies (known as imports) and what capabilities (known as exports) it makes available. When a part is created, the MEF composition engine satisfies its imports with what is available from other parts.