Command Line Calculator: Windows DOS prompt calculator

Command Line Calculator screenshot

From the website:

This is an easy to use calculator that can be run from any Windows DOS prompt. The beauty of this command line calculator is that not only can you do simple calculations while doing other chores, but you have a ticker tape where you can scroll back up and see previous results. Also, running from the command line makes passing the results to other programs or into a file very easy.

Command Line Calculator supports most common mathematical expressions such as sin, cos, tan, log, exp, random number generation, etc.