calculating salary

'hi i'm having problem with calcolating the total it gives me zero
' can any one help me with that

Private Sub Button12_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button12.Click
Dim advanced As Double
Dim benefit As Double
Dim basic As Double
Dim hra As Double
Dim med_all As Double
Dim child As Double
Dim hma As Double
Dim total As Double

advanced = Convert.ToDouble(TextBox6.Text)
benefit = Convert.ToDouble(TextBox7.Text)
basic = Convert.ToDouble(TextBox8.Text)
hra = Convert.ToDouble(TextBox9.Text)
med_all = Convert.ToDouble(TextBox10.Text)
child = Convert.ToDouble(TextBox11.Text)
hma = Convert.ToDouble(TextBox12.Text)
total = Convert.ToDouble(TextBox13.Text)

TextBox6.Text = advanced.ToString
TextBox7.Text = benefit.ToString
TextBox8.Text = basic.ToString
TextBox9.Text = hra.ToString
TextBox10.Text = med_all.ToString
TextBox11.Text = child.ToString
TextBox12.Text = hma.ToString
TextBox13.Text = total.ToString

hra = hra * 5 / 100 * 100
med_all = med_all * 5 / 100 * 100
child = child * 5 / 100 * 100
hma = hma * 8 / 100 * 100
total = basic + advanced + benefit + hra + med_all + child + hma

End Sub