different cell inputs in different cells

Hai all.
I'm a total new bee on VBA and learn now in the past day's a lot.
But i stubbled on to a problem.
I hope you all can help we with it.

The script that i post works the way i want it but it is working only on one cel.
Explanation off the script:
When you put the letters TVT in cel A1 then the script gives a inputbox.
The inputbox fills a different cel with the value you type in the inputbox.
If you delete the tekst TVT than it gives you a warning.

Can somewone make from 3 scripts one?

Private Sub Worksheet_Change(ByVal Target As Range)
Application.EnableEvents = False
If Target.Address(0, 0) = "A1" Then
    Select Case LCase(Target.Value)
        Case "tvt": Call tvturen
        Case Else: MsgBox "Do not Delete"
    End Select
End If
Application.EnableEvents = True
End Sub

Sub Numeric_tvturen()

If Range("A1").Value = "tvt" Then
    tvtsub
    End If
   End Sub
Sub tvtsub()

UserValue = InputBox("TVT uren")
Range("A10").Value = UserValue

End Sub

Which cells do you mean, is it one column?