Factorials

Public Function Factorial(ByVal iValue As Integer) As Long 
Dim fact As Long 
Dim icount As Integer 
   fact = 1 
   For icount = 1 To iValue 
      fact = icount * fact 
   Next icount 
   Factorial = fact 
End Function 

Using a recursive function

Public Function FactorialR(ByVal iValue As Integer) As Long 
   If ( (iValue = 0) Or (iValue = 1) ) Then 
      FactorialR = 1 
   Else 
      FactorialR = FactorialR(iValue - 1) * iValue 
   End If 
End Function