GaryC wrote...
I tried to copy
=AVERAGE(INDEX(A6:W6,MATCH(10,MMULT(--ISNUMBER(A6:W6),
--(COLUMN(A6:W6)<=TRANSPOSE(COLUMN(A6:W6)))),0)):W6)
into my spreadsheet and it treats it as text not a formula.

Make sure there are no leading spaces before the initial = character.
Some browser-based newsgroup portals, like Google Groups, add invisible
characters that screw up copying from your browser and pasting into
Excel.