Ответ:

  1. \(3.12\cdot6=18.72\).
  2. \(12.4\cdot3.12=38.688\).
  3. \(0.23\cdot13.211=3.03853\).
  4. \(4.32\cdot1.1=4.752\).

Ответ: 18,72; 38,688; 3,03853; 4,752.