Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.CenterToScreen()
TextBox1.Text = "50641207018-3"
TextBox2.Text = "นางสาวศรัญญา คำศรี"
TextBox3.Text = "40"
TextBox4.Text = "45"
End Sub

Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim m, f, t As Single
Dim g As String
m = Val(TextBox3.Text)
f = Val(TextBox4.Text)
t = m + f
Label5.Text = Format(t, "##0")
If t < 49.5 Then
g = "F"
ElseIf t <= 59.5 Then
g = "D"
ElseIf t <= 69.5 Then
g = "C"
ElseIf t <= 79.5 Then
g = "B"
Else
g = "A"
End If
Label6.Text = g
End Sub
End Class