Ответ:

  1. 54:(9 · 3)+32 = 54:27+32 = 2+32 = 34.
  2. 420+(640−220):7 = 420+420:7 = 420+60 = 480.
  3. 15 · 5+21 · 2 = 75+42 = 117.
  4. 70 · 4+290−70 = 280+290−70 = 500.