PEMDAS Widget is a simple yet powerful and easy-to-use scientific calculator for Mac OS X Dashboard. Not only does PEMDAS Widget let you work with equations, variables, different bases, and many different functions, but since it runs in Dashboard, it's very lightweight and is always just a key press away. And best of all, it's free!!

Features:

Equations
• The most importart feature of PEMDAS is to let you work with equations. Simply type in an equation, hit enter, and you have the answer! There isn't any messing around like with the one-step-at-a-time calculators.

Number Formatting
• With PEMDAS you can display numbers in floating point notation, scientific and engineering notation, as a percent, and in binary, octal, and hexademical. Additionally, you can limit the number of decimals and significant figures displayed, and turn thousands separators on/off.

Instant Access
• PEMDAS Widget runs in Dashboard with all your other widgets, so there's no need to launch an app to do a few quick calculations -- it's always just key press or click away!
Variables
• PEMDAS lets you work with variables. Assigning a variable is straightforward, simply use the equals sign (example: a = 2+2). What's more PEMDAS automatically assigns the result of every equation you calculate to a unique variable, providing easy access to the results of all equations!

Variable Quick Look
• When you're typing in a variable name, simply move the mouse over the variable name while holding the Shift key to see the value of the variable!

For Engineers, Scientists, and Programmers
• PEMDAS Widget is designed with engineers, scientists, and programmers in mind. Not only can you enter binary, octal, and hex numbers by using the 0b, 0o, and 0x prefixes, format numbers in scientific and engineering notation, and use the percent sign as a modulus operator, but it also supports functions like round(), ciel(), and floor(), as well as the hyperbolic functions.

Requirements:
OS X 10.8+
Intel