Emily8 wrote:
I have a user who is trying to add a number of different cells
toghehter.
Sometimes they have a value and sometimes they are blank. The formula
is
evulating to #Value!.

This is the formula:
I16+K16+M16+O16+Q16+S16+U16+W16+Y16+AA16+AC16+AE1 6
....

As others have already pointed out, the cells that appear blank almost
certainly contain text, and you can't use text that doesn't look like
numbers as operands for arithmetic operators. Yet another work around
(though Bernie's approach would be best),

=N(I16)+N(K16)+N(M16)+N(O16)+N(Q16)+N(S16)+N(U16)+ N(W16)+N(Y16)+N(AA16)
+N(AC16)+N(AE16)