Ответ:

  1. \(2-0.003+0.4-0.01=2.387\).
  2. \(\frac{6.7-2.5}{2.4}=\frac{4.2}{2.4}=1.75\).
  3. \(\frac{11}{18}-\frac49\cdot\frac3{16}=\frac{11}{18}-\frac1{12}=\frac{22-3}{36}=\frac{19}{36}\).
  4. \(\frac{1}{1-\frac{1}{1-\frac19}}=\frac{1}{1-\frac98}=\frac{1}{-\frac18}=-8\).

Ответ: 1) 2,387; 2) 1,75; 3) \(\frac{19}{36}\); 4) −8.