I am a math teacher who uses Word 2008 on the Mac, and I need to collaborate with other teachers who are using Word 2007 under Windows. When they send me a document with mathematical equations in it, I can open it but cannot see the equations or the document loses formatting, such as superscript for exponents.

On this page of Known Issues in Word 2008, Microsoft says,

Equations saved from Word 2007 for Windows do not appear in Word 2008 for Mac

Equations saved in Word 2007 for Windows are not supported in Word 2008 for Mac. The equations will be preserved so that they display correctly in Word 2007, but will appear as placeholders in Word 2008.

What can I do to collaborate with users of Word 2007 on mathematical documents?