Try one of these:

You didn't say "how" your subtraction should work so I'll assume you want to
subtract this value from cell A1:

=A1-INDEX(E:E,K12)

=A1-IF(K12="",0,INDIRECT("E"&K12))

Biff

"Tommy" wrote in message
oups.com...
I'm having trouble finding a function or its syntax to do the
following.
I have a numeric value in a cell, say k12 whose value is 5.
Based on this value 5. I want to perform a mathmatical operation like
subtraction using cell E5. So the value in k12 specifies the row of
column E I want to use.
Logically I picture the syntax as being =E(k12), which would use the
value in E5 for my further calculations. This of course doesn't work
out.
Can anybody help?