Aha, very interesting. I certainly did not know that.
Thank you so much for the answer. Have a nice day ;)

Regards
Jan

"David Biddulph" skrev i melding
...
The "double unary minus" converts a logical (TRUE or FALSE) value to a
number (1 or 0).
--
David Biddulph

"Jan T." wrote in message
...
Thank you very much for helping.
But can you tell me, what does the two minus before (--ISNUMBER... do?

Jan

"Teethless mama" skrev i
melding ...
=SUMPRODUCT(--ISNUMBER(SEARCH("K",A1:F1)))