Ответ:

  1. \(124\cdot6=744\).
  2. \(208\cdot4=832\).
  3. \(24\cdot19=24\cdot(20-1)=480-24=456\).
  4. \(35\cdot28=35\cdot(20+8)=700+280=980\).
  5. \(240\cdot4=960\).
  6. \(16\cdot16=256\).
  7. \(798\cdot7=(800-2)\cdot7=5\,600-14=5\,586\).
  8. \(585\cdot9=(600-15)\cdot9=5\,400-135=5\,265\).

Ответ: 744; 832; 456; 980; 960; 256; 5 586; 5 265.