Bookmarks
Any arbitrary piece of text and/or graphics in a WordprocessingML document can be assigned a name, called a bookmark. If a bookmark references text that represents an expression, that bookmark's name can be used as an operand in another expression. If a whole field is bookmarked, its bookmark name can also be used as an operand in an expression.
example: : Given that
X
is a bookmark for the text 4, Y
is a bookmark for the text 2, and Result
is a bookmark for the following field:=X + Y
the field
=Result * 10
has the result 60
. ]