Ответ:

а)

  1. \(6 \cdot 9 = 54\)
  2. \(63 : 9 = 7\)
  3. \(5 \cdot 7 = 35\)
  4. \(48 : 8 = 6\)
  5. \(16 \cdot 4 = 64\)
  6. \(76 : 4 = 19\)

б)

  1. \(376 + 292 = 668\)
  2. \(726 - 432 = 294\)
  3. \((630 - 30) : 10 = 600 : 10 = 60\)
  4. \(720 : 9 + 40 = 80 + 40 = 120\)

Ответ: 54; 7; 35; 6; 64; 19; 668; 294; 60; 120.