1. Public Class Form1
Dim total As Double
Dim total1 As Double
Dim operation As String
Private Sub zero_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
zero.Click
TextBox1.Text = TextBox1.Text & zero.Text
End Sub
Private Sub one_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
one.Click
TextBox1.Text = TextBox1.Text & one.Text
End Sub
Private Sub two_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
two.Click
TextBox1.Text = TextBox1.Text & two.Text
End Sub
Private Sub three_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
three.Click
TextBox1.Text = TextBox1.Text & three.Text
End Sub
Private Sub four_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
four.Click
TextBox1.Text = TextBox1.Text & four.Text
End Sub
Private Sub five_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
five.Click
TextBox1.Text = TextBox1.Text & five.Text
End Sub
Private Sub six_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
six.Click
TextBox1.Text = TextBox1.Text & six.Text
End Sub
Private Sub seven_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
seven.Click
TextBox1.Text = TextBox1.Text & seven.Text
End Sub
Private Sub eight_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
eight.Click
TextBox1.Text = TextBox1.Text & eight.Text
End Sub
Private Sub nine_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
nine.Click
TextBox1.Text = TextBox1.Text & nine.Text
End Sub
Private Sub plus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
plus.Click
operation = "+"

2. total = total + Val(TextBox1.Text)
TextBox1.Text = " "
End Sub
Private Sub Mul_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
Mul.Click
operation = "*"
total = total + Val(TextBox1.Text)
TextBox1.Text = " "
End Sub
Private Sub equal_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
equal.Click
If operation = "+" Then
total1 = total + Val(TextBox1.Text)
total = 0
ElseIf operation = "*" Then
total1 = total * Val(TextBox1.Text)
total = 0
ElseIf operation = "-" Then
total1 = total - Val(TextBox1.Text)
total = 0
ElseIf operation = "" Then
total1 = total Val(TextBox1.Text)
total = 0
End If
TextBox1.Text = total1.ToString()
End Sub
Private Sub minus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
minus.Click
operation = "-"
total = total + Val(TextBox1.Text)
TextBox1.Text = " "
End Sub
Private Sub div_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
div.Click
operation = ""
total = total + Val(TextBox1.Text)
TextBox1.Text = " "
End Sub
Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
Cancel.Click
TextBox1.Text = " "
End Sub
Private Sub CE_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
CE.Click
TextBox1.Text = ""
total1 = 0
End Sub
Private Sub dot_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
dot.Click

3. TextBox1.Text = TextBox1.Text & "."
End Sub
End Class