I need help with the following code as I do not know how to read a string and return the 1st three values.

Sub test()

    Dim iZip As String, parsed_zip As Variant

    valid = False
    Do Until valid = True
    iZip = Application.InputBox(prompt:="Enter Zipcode", Title:="Zipcode", Left:=300, Top:=250, Type:=1)
    If iZip <> Empty And iZip <> "False" Then
            valid = True
        End If
    Loop
    inp_form.Range("F5").Value = iZip
    
    'need code to read 1st 3 digits of iZip and output to variable parsed_zip
    
    Select Case parsed_zip
        Case 620 To 629
        Case Else
    End Select

End Sub