Ответ:

  1. \(0.2+5.81=6.01\).
  2. \(-1.2-4=-5.2\).
  3. \(0.3-5.25=-4.95\).
  4. \(\frac35\cdot(-15)=-9\).
  5. \(1\frac27\cdot\left(-\frac3{14}\right)=\frac97\cdot\left(-\frac3{14}\right)=-\frac{27}{98}\).
  6. \(1\frac23-0.9=\frac53-\frac9{10}=\frac{50-27}{30}=\frac{23}{30}\).

Ответ: 6,01; −5,2; −4,95; −9; −27/98; 23/30.