A family of Microsoft word processing software products for creating web, email, and print documents.
A common way to do this is to use a two-column table where you put the equation in the left column and a SEQ field in the right column.
With the "new" equation feature (introduced in Word 2007), you can type # at the end of an equation and type (). Then press Enter and you will get this result:
In the placeholder you just created, you can insert a SEQ field for numbering.