dateadd

Hi i m new in B4A and i try to use date operation but it will give me wrong results??? dim dtn as long DateTime.DateFormat = "yyyy/mm/dd" dtn = DateTime.Now log( datetime.date(dtn)) ' it will give for today 2018/18/31 not normally 2018/07/31????? is it a bugg???? or i do some mistake???? Hery