There is a very simple command line calculator available by typing bc in a terminal window and pressing the Enter key. To see how it works, type 2+2 and press the Enter key to see the result. The calculator is cleared automatically between each equation, so you can enter as many equations as you like. To exit, press the Ctrl and d keys at the same time or type quit and press the Enter key.
Obligatory Happy Ending
And they all lived happily ever after. The end.