Ответ:

  1. 407999 + 1 = 408000.
  2. 599999 + 1 = 600000.
  3. 999999 + 1 = 1000000.
  4. 80000 − 1 = 79999.
  5. 72000 − 1 = 71999.
  6. 3280 − 1 = 3279.