The Daum Equation Editor is a free add-on web app for Google Chrome that allows you to easily and quickly create and edit a formula. This is a great resource for math and science educators and students because now they can use formulas in web apps and Google Docs much easier. The equations can be saved as text or images and then inserted in documents or web sites. The equation editor has a nice menu to use for selecting symbols and functions and you can modify the size and font of the equation.
Check it out in the Chrome Web Store.