How to use numpad as input in vb calculator - vb.net

Question

Basically I've been searching for weeks now but I cannot find a good example of using the numpad as an input for calculator.
Private Sub Form1_KeyPress(ByVal KeyAscii As _MSForms.ReturnInteger)
lblOutput.Text = lblOutput.Text & Chr(KeyAscii)
If KeyAscii >= vbKeyNumpad0() And KeyAscii <= vbKeyNumpad9() Then
lblOutput.Text = lblOutput.Text & Chr(KeyAscii)
End If
End Sub
Option Explicit On
Public Class Form1
Dim chrOperator As Char
Dim varFirstVal As Integer
Private Sub Form1_KeyPress(ByVal KeyAscii As _MSForms.ReturnInteger)
lblOutput.Text = lblOutput.Text & Chr(KeyAscii)
If KeyAscii >= vbKeyNumpad0() And KeyAscii <= vbKeyNumpad9() Then
lblOutput.Text = lblOutput.Text & Chr(KeyAscii)
End If
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
KeyPreview = True
End Sub
Private Sub ButtonAppend(number As Integer)
If CInt(lblOutput.Text) = 0 Then
lblOutput.Text = CType(number, String)
Else
lblOutput.Text = lblOutput.Text & number
End If
End Sub
Private Sub operation(operand As String)
chrOperator = CChar(operand)
varFirstVal = CInt(lblOutput.Text)
lblOutput.Text = CType(0, String)
End Sub
Private Sub btn1_Click(sender As Object, e As EventArgs) Handles btn1.Click
ButtonAppend(1)
End Sub
Private Sub btn2_Click(sender As Object, e As EventArgs) Handles btn2.Click
ButtonAppend(2)
End Sub
Private Sub btn3_Click(sender As Object, e As EventArgs) Handles btn3.Click
ButtonAppend(3)
End Sub
Private Sub btn4_Click(sender As Object, e As EventArgs) Handles btn4.Click
ButtonAppend(4)
End Sub
Private Sub btn5_Click(sender As Object, e As EventArgs) Handles btn5.Click
ButtonAppend(5)
End Sub
Private Sub btn6_Click(sender As Object, e As EventArgs) Handles btn6.Click
ButtonAppend(6)
End Sub
Private Sub btn7_Click(sender As Object, e As EventArgs) Handles btn7.Click
ButtonAppend(7)
End Sub
Private Sub btn8_Click(sender As Object, e As EventArgs) Handles btn8.Click
ButtonAppend(8)
End Sub
Private Sub btn9_Click(sender As Object, e As EventArgs) Handles btn9.Click
ButtonAppend(9)
End Sub
Private Sub btn0_Click(sender As Object, e As EventArgs) Handles btn0.Click
ButtonAppend(0)
End Sub
Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
lblOutput.Text = "0"
varFirstVal = 0
End Sub
Private Sub btnEquals_Click(sender As Object, e As EventArgs) Handles btnEquals.Click
Select Case chrOperator
Case CChar("A")
lblOutput.Text = CType(varFirstVal + CInt(lblOutput.Text), String)
Case CChar("S")
lblOutput.Text = CType(varFirstVal - CInt(lblOutput.Text), String)
Case CChar("M")
lblOutput.Text = CType(varFirstVal * CInt(lblOutput.Text), String)
Case CChar("D")
lblOutput.Text = CType(varFirstVal / CInt(lblOutput.Text), String)
End Select
End Sub
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
operation("A")
End Sub
Private Sub btnSub_Click(sender As Object, e As EventArgs) Handles btnSub.Click
operation("S")
End Sub
Private Sub btnMultiply_Click(sender As Object, e As EventArgs) Handles btnMultiply.Click
operation("M")
End Sub
Private Sub btnDivide_Click(sender As Object, e As EventArgs) Handles btnDivide.Click
operation("S")
End Sub
End Class
What I want to get out of it is being able to use the numpad and never have to click anything on screen for the calculator to work.