Question about the use of "--" in a formula

[dcgrove]

What does the double minus signs mean when you use it in a formula?

example formula:

=SUMPRODUCT(--(LEFT($A$7:$A$675,5)+0>=60000),--(LEFT($A$7:$A$675,5)+0<=60999),AL7:AL675)

[DonkeyOte]

It is the double unary operator and is used to coerce Boolean to Integer equivalent (TRUE -> 1, FALSE -> 0)

For more info. on SUMPRODUCT and coercion see the link to the function in my sig. to Bob Phillips' white paper.

[dcgrove]

Thanks for the help!