It's subtracting 1 and 7 in order to count the number of Sundays (weekday 1)
and Saturdays (weekday 7) in the month.

That formula can be replaced with:

=NETWORKDAYS(C3,DATE(YEAR(C3),MONTH(C3)+1,0))

With C3 = 1/1/2007

The result is 23 with both formulas.

Biff

"David" wrote in message
...
Gidday

I am seeking a bit of help with what the "-{1,7}" does/means in the
following formula;
=ABS(IF((DATE(YEAR(C3),MONTH(C3)+1,DAY(C3))),(C3)-(DATE(YEAR(C3),MONTH(C3)+1,DAY(C3)))-SUM(INT((WEEKDAY((DATE(YEAR(C3),MONTH(C3)+1,DAY(C3 )))-{1,7})+(C3)-(DATE(YEAR(C3),MONTH(C3)+1,DAY(C3))))/7)),""))

The forumal works out the number of workdays in a month where C3= 1/1/2007
and the return answer is 20

I look forward to your responses.