Ответ:

  1. \(40:5=8\), \(8\cdot3=24\), \(24:6=4\), \(4+46=50\).
  2. \(72:8=9\), \(9+11=20\), \(20:5=4\), \(4\cdot9=36\).
  3. \(28:7=4\), \(4\cdot8=32\), \(32+8=40\), \(40:10=4\).
  4. \(56:8=7\), \(7+13=20\), \(20:4=5\), \(5\cdot8=40\).

Ответ: цепочки: 40 → 8 → 24 → 4 → 50; 72 → 9 → 20 → 4 → 36; 28 → 4 → 32 → 40 → 4; 56 → 7 → 20 → 5 → 40.