I can't for the life of me remember how to denote a fixed
cell in a formula. For example, I want each cell in a
column to be divided by a single cell, A15. If I just
enter A15 into the formula and copy the formula down the
column, each cell will be divided by A15, A16, A17
progressively on down the line. How do I fix A15 as a
constant in the formula??!!

Thanks to anyone who can refresh my memory.