In the October 2001 “Technology Q&A,” we described how to use the dollar symbol ($) in Excel formulas to make formulas constant—so if you copy them to a different cell they won’t automatically change to reflect their new location.
An easier way is to double-click on the cell to be moved or duplicated and type an apostrophe (’) in front of the formula. This transforms the cell into a text—not a formula—cell. Then, after you copy or move it, you simply delete the apostrophe and the cell reference will remain unchanged.
From Lanny D. Levin of the Lanny D. Levin Agency in Highland Park, Illinois.