ISNUMBER returns a value of TRUE or FALSE. To convert these to
their numeric equivalent (1 or 0), the double negative sign is
used. It takes the negative of a negative, which coerces the TRUE
or FALSE value to numbers.


--
Cordially,
Chip Pearson
Microsoft MVP - Excel
Pearson Software Consulting, LLC
www.cpearson.com


"Gunjani" wrote in message
oups.com...
Why the "--" before ISNUMBER

Regards

Gunjani