Ответ:

а)

  1. \(25 \cdot 4 = 100\), \(7 \cdot 6 = 42\), \(72 - 46 = 26\).
  2. \(42 + 18 = 60\), \(60 : 3 = 20\), \(0 \cdot 26 = 0\).
  3. \(100 - 20 + 0 = 80\).

Ответ: 80.

б)

  1. \(23 + 49 - 15 = 57\), \(56 : 8 = 7\), \(5 \cdot 1 = 5\).
  2. \(0 : 57 = 0\), \(7 + 5 = 12\), \(12 \cdot 3 = 36\).
  3. \(96 + 0 - 36 = 60\).

Ответ: 60.