2. Действия с обыкновенными дробями.

1) $\frac{1}{5} + \frac{53}{50} = \frac{10}{50} + \frac{53}{50} = \frac{63}{50} = 1\frac{13}{50}$ 2) $\frac{9}{4} + \frac{8}{5} = \frac{45}{20} + \frac{32}{20} = \frac{77}{20} = 3\frac{17}{20}$ 3) $\frac{1}{10} + \frac{6}{15} = \frac{3}{30} + \frac{12}{30} = \frac{15}{30} = \frac{1}{2}$ 4) $\frac{1}{5} - \frac{47}{10} = \frac{2}{10} - \frac{47}{10} = -\frac{45}{10} = -\frac{9}{2} = -4\frac{1}{2}$ 5) $\frac{9}{4} - \frac{8}{5} = \frac{45}{20} - \frac{32}{20} = \frac{13}{20}$ 6) $\frac{11}{12} - \frac{5}{18} = \frac{33}{36} - \frac{10}{36} = \frac{23}{36}$ 7) $\frac{9}{5} \cdot \frac{2}{3} = \frac{3 \cdot 2}{5 \cdot 1} = \frac{6}{5} = 1\frac{1}{5}$ 8) $\frac{15}{4} \cdot \frac{6}{5} = \frac{3 \cdot 3}{2 \cdot 1} = \frac{9}{2} = 4\frac{1}{2}$ 9) $\frac{2}{3} \cdot \frac{9}{8} = \frac{1 \cdot 3}{1 \cdot 4} = \frac{3}{4}$ 10) $\frac{6}{5} : \frac{4}{11} = \frac{6}{5} \cdot \frac{11}{4} = \frac{3 \cdot 11}{5 \cdot 2} = \frac{33}{10} = 3\frac{3}{10}$ 11) $\frac{12}{5} : \frac{15}{2} = \frac{12}{5} \cdot \frac{2}{15} = \frac{4 \cdot 2}{5 \cdot 5} = \frac{8}{25}$ 12) $\frac{6}{11} : \frac{3}{22} = \frac{6}{11} \cdot \frac{22}{3} = 2 \cdot 2 = 4$ 13) $(\frac{13}{30} - \frac{11}{20}) \cdot \frac{9}{5} = (\frac{26}{60} - \frac{33}{60}) \cdot \frac{9}{5} = -\frac{7}{60} \cdot \frac{9}{5} = -\frac{7 \cdot 3}{20 \cdot 5} = -\frac{21}{100}$ 14) $(\frac{17}{15} - \frac{1}{12}) \cdot \frac{20}{3} = (\frac{68}{60} - \frac{5}{60}) \cdot \frac{20}{3} = \frac{63}{60} \cdot \frac{20}{3} = \frac{21}{20} \cdot \frac{20}{3} = \frac{21}{3} = 7$ 15) $\frac{14}{5} \cdot (\frac{3}{14} - \frac{5}{28}) = \frac{14}{5} \cdot (\frac{6}{28} - \frac{5}{28}) = \frac{14}{5} \cdot \frac{1}{28} = \frac{1}{5 \cdot 2} = \frac{1}{10}$ 16) $(\frac{11}{18} + \frac{2}{9}) : \frac{5}{48} = (\frac{11}{18} + \frac{4}{18}) : \frac{5}{48} = \frac{15}{18} : \frac{5}{48} = \frac{5}{6} \cdot \frac{48}{5} = 8$ 17) $(\frac{11}{10} - \frac{4}{11}) : \frac{15}{44} = (\frac{121}{110} - \frac{40}{110}) : \frac{15}{44} = \frac{81}{110} \cdot \frac{44}{15} = \frac{27}{5} \cdot \frac{2}{5} = \frac{54}{25} = 2\frac{4}{25}$ 18) $(\frac{6}{8} - \frac{3}{16}) : \frac{3}{32} = (\frac{12}{16} - \frac{3}{16}) : \frac{3}{32} = \frac{9}{16} \cdot \frac{32}{3} = 3 \cdot 2 = 6$