Finding the number of workdays (Monday through Friday) between two dates can't be done by simply subtracting one date from another. It requires a prewritten formula called the NETWORKDAYS function, which calculates the net number of workdays between two dates.
It's still June 9, 2004, and your vacation still starts on August 21, 2004, but now you want to find how many workdays until vacation. You would type the formula into an empty cell:
There are 53 workdays until vacation. The values in cells A2 and A3 are the arguments, information that tells NETWORKDAYS what to calculate. Parentheses separate the function from the arguments. Within the parentheses, a comma separates the arguments from each other.