How to get first day and last day of current and previous month

To get the first day of the current month,

  CALCDATE ('<CM-1M+1D>', Today);

To get the Last day of the current month,

    CALCDATE ('<CM>', Today).

To get the first day of the previous month,

     CALCDATE ('<CM-2M+1D>', Today);

To get the Last day of the Previous month,

       CALCDATE('<CM>',CALCDATE('<-CM-1D>',TODAY)).