Ответ:

  1. \(|4.5|+|-2.3|=4.5+2.3=6.8\).
  2. \(|-13|\cdot|-6|=13\cdot6=78\).
  3. \(\left|-\frac7{18}\right|-\left|-\frac5{12}\right|=\frac7{18}-\frac5{12}=\frac{14-15}{36}=-\frac1{36}\).

Ответ: а) 6,8; б) 78; в) \(-\frac1{36}\).