Hi Pecoflyer,
This was very close:
=SUM(a2:u2)-SUM(OFFSET(A2,,,,MATCH(0,A2:U2,0))).

But it adds cells together to the first cell="0" from Right-to-Left + Left-to-Right.
I was looking for only the Right-to-Left if you can modify.

thank you again for your diligence.

sunny