Ответ:

  1. \(12\cdot3=36\);
  2. \(13\cdot4=52\);
  3. \(18:2=9\);
  4. \(12:3=4\);
  5. \(340+298=638\);
  6. \(392-204=188\);
  7. \(597-319=278\);
  8. \(905-698=207\).

Ответ: 36; 52; 9; 4; 638; 188; 278; 207.