A) $$1-\frac{5}{11}$$; И) $$3\frac{5}{6} - 1\frac{4}{9}$$

A) $$1 - \frac{5}{11} = \frac{11}{11} - \frac{5}{11} = \frac{11-5}{11} = \frac{6}{11}$$
И) $$3\frac{5}{6} - 1\frac{4}{9} = \frac{3 \cdot 6 + 5}{6} - \frac{1 \cdot 9 + 4}{9} = \frac{18+5}{6} - \frac{9+4}{9} = \frac{23}{6} - \frac{13}{9} = \frac{23 \cdot 3}{6 \cdot 3} - \frac{13 \cdot 2}{9 \cdot 2} = \frac{69}{18} - \frac{26}{18} = \frac{69-26}{18} = \frac{43}{18} = 2\frac{7}{18}$$