Kod:
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
TextBox3.Text = Val(TextBox1.Text) + Val(TextBox2.Text)
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
TextBox3.Text = Val(TextBox1.Text) - Val(TextBox2.Text)
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
TextBox3.Text = Val(TextBox1.Text) * Val(TextBox2.Text)
End Sub
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
TextBox3.Text = Val(TextBox1.Text) / Val(TextBox2.Text)
End Sub
End Class