iota-calc for Mac OS X 188.8.131.52
Supports a rich expression format, which is in most cases identical to what you would type in your programming language.
Support for adding an unlimited number of variables.
Built-in debugger that lets you see the expression simplified step by step.
Debugger Back-step lets you backup as many steps as you like so that you can replay critical operations.
C/C++ operator precedence
Mouse optional, all calculator commands and...