Ответ:

  1. 70000 + 600 = 70600
  2. 28000 − 20000 = 8000
  3. 64500 − 500 = 64000
  4. 726000 − 20000 = 706000
  5. 20000 + 200 + 6 = 20206
  6. 300000 + 10000 + 400 = 310400