Michael Filippone has released PEMDAS 2.0 (http://donkeyengineering.com/pemdaswidget/), an update of a free scientific calculator widget for Mac OS X (10.5.8 and later). The first major update to PEMDAS 1.1, which won the 2007 Apple Design Award for Best Dashboard Widget, Runner-Up, the latest version offers refinements and expanded features.
Version 2.0 features a new, sleeker keypad and equation history view, and adds a third, mini-view, which reduces the view to just equation and answer. The equation history view has been redesigned, and now displays equations with their results directly below, as well as a list of all variables in the current session.
Nearly the entire interface has been re-written in response to user feedback, says Filippone. Every aspect of its graphical user interface, keypad layout, use of color, typography, display and entry fields, and keyboard shortcuts contribute to the usability of PEMDAS, he adds.