Private Sub Raschet_Click()
   Raschet_na_deni VelVB, VelNB, 0
End Sub
Private Sub Raschet_na_deni(VB As Single, NB As Single, Vtek As Single)
         Moduli_rascheta
End Sub

Option Explicit
Dim VB As Single
Dim NB As Single
Dim Vtek As Single
Dim VelVB As Single
Dim VelNb As Single
Dim Napor As Single
Private Sub Raschet_Click()
   Vtek = 0
   VelNb = 1
   VelVB = 2
       Raschet_na_deni VelNb, VelVB, 0
End Sub
Private Sub Raschet_na_deni(NB As Single, VB As Single, Vtek As Single)
        Moduli_rascheta
End Sub
Private Sub Moduli_rascheta()
    Dim dll2 As Object
         On Error Resume Next
             Set dll2 = CreateObject("CalcMod.Class1")
                If Err.Number <> 0 Then
              End If
           Napor = Format(dll2.MyfuncVB(VB) - dll2.MyfuncNB(NB), "0.00")
End Sub