Ответ:

  1. \(389-(57+189)=389-189-57=200-57=143\).
  2. \(8963-(963+500)=8963-963-500=8000-500=7500\).
  3. \(254-(154-87)=254-154+87=100+87=187\).
  4. \((870+738)-70=870-70+738=800+738=1538\).
  5. \((86+1037)-1027=86+(1037-1027)=86+10=96\).