Hi Suresh,
In Word 2007 there is a new equation editor built in and coloring equations is pretty similar to other text.
For earlier versions of Office, you can color MS Equation Editor 3.0 equations in Powerpoint but not in Word. You can color them in
Word if you upgrade to it's full featured product, MathType (
http://mathtype.com).
Without upgrading you can add a border or a
colored background or highlight, but the equation color stays black.
As an option, when finalizing your document (save a copy of the file under a different name) you can copy the equation object object
into a Powerpoint slide and then use the Powerpoint Picture toolbar's 'recolor' choice to change the color of the Equation object,
then copy it back to Word, but paste it as an Enhanced Metafile (picture) [you won't be able to reedit it].
As another possibility you can use, instead of the MS Equation Editor the Word "EQ" (equation) field from Insert=>Field.
Equations created with the field method can be colored as regular text, but there is a bit of a learning curve to getting this to
work if you have sophisticated equations. In Word Help search on
field equation
to get started.
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how to change the color of the equations created using equation editor?>>
--
Bob Buckland ?

MS Office System Products MVP
*Courtesy is not expensive and can pay big dividends*