Need help with formula

[JB]

I tried using this formula to count how many days between two specific
days. I receive a wrong number of arguments error when using the
fucntion below. Any idea's why it won't work?

=Count(IIf([Days Old]>=3 and [Days Old]<=10))

 

[Guest]

Why aren't you just using the DATEDIFF function?

 

[John Spencer]

One method would be

=Count(IIf([Days Old]>=3 and [Days Old]<=10,1,Null))

Another
=Abs(Sum(IIf([Days Old]>=3 and [Days Old]<=10))