Решение примеров:

а) $$rac{4}{11} + \frac{7}{22} = \frac{4 \cdot 2}{11 \cdot 2} + \frac{7}{22} = \frac{8}{22} + \frac{7}{22} = \frac{8+7}{22} = \frac{15}{22}$$

б) $$rac{9}{12} - \frac{4}{15} = \frac{9 \cdot 5}{12 \cdot 5} - \frac{4 \cdot 4}{15 \cdot 4} = \frac{45}{60} - \frac{16}{60} = \frac{45-16}{60} = \frac{29}{60}$$

в) $$rac{13}{15} - \frac{7}{20} + \frac{11}{30} = \frac{13 \cdot 4}{15 \cdot 4} - \frac{7 \cdot 3}{20 \cdot 3} + \frac{11 \cdot 2}{30 \cdot 2} = \frac{52}{60} - \frac{21}{60} + \frac{22}{60} = \frac{52 - 21 + 22}{60} = \frac{53}{60}$$

г) $$\frac{41}{45} - 0,32 = \frac{41}{45} - \frac{32}{100} = \frac{41}{45} - \frac{8}{25} = \frac{41 \cdot 5}{45 \cdot 5} - \frac{8 \cdot 9}{25 \cdot 9} = \frac{205}{225} - \frac{72}{225} = \frac{205 - 72}{225} = \frac{133}{225}$$

Ответ: a) 15/22; б) 29/60; в) 53/60; г) 133/225.