If you have 64-bit Office 2010 you need MathType 6.8

MathType 6.8 for Windows is fully compatible with Microsoft Office 2010 (32 & 64-bit) as well as Windows 7 and 600+ other applications!


MathType functionality with Office:

• MathType Ribbon Tab in Word and PowerPoint: MathType takes full advantage of Office's Ribbon User   Interface making it easier than ever to do equation operations in documents and presentations. Equation numbering and browse features work with all Word equation types.
• Equations in Outlook: MathType works with Outlook and allows you to include mathematical notation in email. The recipient of your email does not have to use either Outlook or MathType in order to see your equations.
• MathPage for Word 2010 and 2007: Our MathPage™ technology now converts Microsoft Word 2010 and 2007 documents into web pages, properly handling mathematical symbols. Will also display properly for people with print disabilities.
• Handwritten equations: MathType adds a menu command to bring the Windows 7 Math Input Panel to the front, ready for you to enter math by hand. This command is available in any MathType window, as well as within Microsoft Word.

...and more.