Вычисли дроби.

1) $\frac{1}{4} + \frac{3}{5} = \frac{5}{20} + \frac{12}{20} = \frac{17}{20}$ 2) $\frac{9}{11} - \frac{2}{5} = \frac{45}{55} - \frac{22}{55} = \frac{23}{55}$ 3) $\frac{13}{16} - \frac{9}{32} = \frac{26}{32} - \frac{9}{32} = \frac{17}{32}$ 4) $\frac{3}{28} + \frac{5}{14} = \frac{3}{28} + \frac{10}{28} = \frac{13}{28}$ 5) $\frac{14}{15} - \frac{7}{10} = \frac{28}{30} - \frac{21}{30} = \frac{7}{30}$ 6) $\frac{3}{8} + \frac{1}{6} = \frac{9}{24} + \frac{4}{24} = \frac{13}{24}$ 7) $\frac{9}{25} - \frac{7}{20} = \frac{36}{100} - \frac{35}{100} = \frac{1}{100}$ 8) $\frac{37}{42} - \frac{17}{24} = \frac{148}{168} - \frac{119}{168} = \frac{29}{168}$ 9) $\frac{11}{24} - \frac{3}{16} = \frac{22}{48} - \frac{9}{48} = \frac{13}{48}$ 10) $\frac{9}{16} + \frac{7}{24} = \frac{27}{48} + \frac{14}{48} = \frac{41}{48}$ 11) $\frac{1}{36} + \frac{1}{4} = \frac{1}{36} + \frac{9}{36} = \frac{10}{36} = \frac{5}{18}$ 12) $\frac{2}{15} + \frac{4}{9} = \frac{6}{45} + \frac{20}{45} = \frac{26}{45}$ **Ответы:** 1) $\frac{17}{20}$ 2) $\frac{23}{55}$ 3) $\frac{17}{32}$ 4) $\frac{13}{28}$ 5) $\frac{7}{30}$ 6) $\frac{13}{24}$ 7) $\frac{1}{100}$ 8) $\frac{29}{168}$ 9) $\frac{13}{48}$ 10) $\frac{41}{48}$ 11) $\frac{5}{18}$ 12) $\frac{26}{45}$