If A2:B2 contain text which looks like dates, the double unary minus will
convert them to real dates.
Note also that your formula has an m that ought to be a comma.
Note also that "double unary" by itself isn't a very specific term:
-- is a double unary minus
++ would be a double unary plus.
--
David Biddulph

"Daren" wrote in message
...
Hello,

The AND statement is as follows:

=and(--d2--c2,--c2--b2m--b2--a2).

What's the purpose of the double unary here?

Thanks!