Please help

im desgining a scientific calculator and its not completed as yet. at the moment my problem is it is working but say if i multiply 1 by one then i add one to the result and i press the equal button it will show as for. in other words if i change from one operation to another without pressing the equal button it will take the displayed value as if i have entered that value. please take a look at my code and show me some tips to fix it up thanks

Dim i As Integer
Dim sofar As Integer

Private Sub cmdadd_Click()
'If Not (i = 1) Then
'txtdis.Text = " "
'End If
sofar = sofar + Val(txtdis.Text)
txtdis.Text = " "
lblsofar = (sofar)
i = 1
End Sub

Private Sub cmdclear_Click()
txtdis.Text = " "
sofar = 0
End Sub

Private Sub cmddig_Click(Index As Integer) ' the digits from 0 to 9
Dim S As String
Dim i As Integer
S = txtdis.Text
S = S & cmddig(Index).Caption
txtdis.Text = S
End Sub

Private Sub cmdequal_Click()

If i = 1 Then
txtdis = Val(Val(txtdis) + Val(sofar))
End If
If i = 2 Then
'x = MsgBox(i)
txtdis = Val(Val(txtdis) * Val(sofar))
End If
If i = 3 Then
txtdis = Val(Val(sofar) - Val(txtdis))
End If
If i = 4 Then
txtdis = Val(Val(sofar) / Val(txtdis))
End If
lblsofar = sofar
End Sub



Private Sub cmdmultiply_Click()
'If Not (i = 2) Then
'txtdis.Text = " "
'End If
If sofar = 0 Then
sofar = 1
End If
sofar = (sofar) * Val(txtdis.Text)
Me.Print (sofar)
txtdis.Text = " "
i = 2
lblsofar = sofar
End Sub

Private Sub cmdsubtract_Click()
sofar = Val(txtdis.Text) - (sofar)
Me.Print (sofar)
txtdis.Text = " "
i = 3
lblsofar = sofar
End Sub


Private Sub txtdivide_Click()

If sofar = 0 Then
sofar = 1
End If
sofar = Val(Val(txtdis.Text) / (sofar))
x = MsgBox(sofar)
txtdis.Text = " "
i = 4
lblsofar = sofar
End Sub