Ответ:

  1. \( -45 : (-9)=5 \).
  2. \( -78.91 : 13=-6.07 \).
  3. \( -\frac{30}{49} : \left(-\frac{45}{56}\right)=\frac{30}{49}\cdot\frac{56}{45}=\frac{8}{21} \).
  4. \( -1\frac{5}{27} : 2\frac{2}{9}=-\frac{32}{27}:\frac{20}{9}=-\frac{32}{27}\cdot\frac{9}{20}=-\frac{8}{15} \).

Ответ: 1) 5; 2) −6,07; 3) \(\frac{8}{21}\); 4) \(-\frac{8}{15}\).