Fehler: Division durch Null...

Private Sub CommandButton1_Click()
Dim a As Double
Dim b As Double
Dim c As Double
Dim d As Double
Dim e As Double
Dim f As Double
a = TextBox1
b = (a + 0.24)
TextBox3 = b
c = 50 \ b
TextBox4 = c
d = c - 3.79
TextBox5 = d
e = 0.0069
f = d \ e
TextBox2 = f
End Sub

Würde mich sehr freuen, wenn mir jemand helfen könnte. Schonmal danke im Vorraus.

Mfg
Phil