' the Greatest Common Divisor of two integers' (it uses the Euclide's algorithm)' if either argument is zero you get a "Division by Zero" errorFunction GCD(ByVal n1 As Long, ByVal n2 As Long) As Long Dim tmp As Long Do ' swap the items so that n1 >= n2 If n1 < n2 Then tmp = n1 n1 = n2 n2 = tmp End If ' take the modulo n1 = n1 Mod n2 Loop While n1 GCD = n2End Function