Got it, thank you very much. The code I use like this:

Sub copy1()
    Set sbook = Workbooks.Open("C:\tmp\aaa.xls")
    Set dbook = Workbooks.Open("C:\tmp\bbb.xls")
    
    Windows("bbb.xls").Activate
    Sheets("Sheet1").Activate
    Set source = Range("A1:A10")
    
    Windows("aaa.xls").Activate
    Sheets("Sheet1").Activate
    Set dest = Range("A1:A10")
       
    dest.Value = source.Formula
    

End Sub