Вычисли выражения с дробями

Решаю примеры на сложение, вычитание и упрощение дробей: 1) $3 \frac{3}{4} + \frac{4}{7} = \frac{3*4 + 3}{4} + \frac{4}{7} = \frac{15}{4} + \frac{4}{7} = \frac{15*7 + 4*4}{4*7} = \frac{105 + 16}{28} = \frac{121}{28} = 4 \frac{9}{28}$ 2) $13 \frac{3}{24} - \frac{3}{8} = 13 \frac{3}{24} - \frac{3*3}{8*3} = 13 \frac{3}{24} - \frac{9}{24} = 12 \frac{24+3}{24} - \frac{9}{24} = 12 \frac{27-9}{24} = 12 \frac{18}{24} = 12 \frac{3}{4}$ 3) $12 \frac{11}{12} - \frac{5}{18} = 12 \frac{11*3}{12*3} - \frac{5*2}{18*2} = 12 \frac{33}{36} - \frac{10}{36} = 12 \frac{23}{36}$ 4) $\frac{13}{36} + \frac{7}{24} = \frac{13*2}{36*2} + \frac{7*3}{24*3} = \frac{26}{72} + \frac{21}{72} = \frac{47}{72}$ 5) $15 \frac{8}{15} - 2 \frac{4}{9} = 15 \frac{8*3}{15*3} - 2 \frac{4*5}{9*5} = 15 \frac{24}{45} - 2 \frac{20}{45} = 13 \frac{4}{45}$ 6) $6 \frac{5}{6} - 2 \frac{2}{3} + \frac{2}{9} = 6 \frac{5*3}{6*3} - 2 \frac{2*6}{3*6} + \frac{2*2}{9*2} = 6 \frac{15}{18} - 2 \frac{12}{18} + \frac{4}{18} = 4 \frac{3}{18} + \frac{4}{18} = 4 \frac{7}{18}$ **Ответы:** 1) $4 \frac{9}{28}$ 2) $12 \frac{3}{4}$ 3) $12 \frac{23}{36}$ 4) $\frac{47}{72}$ 5) $13 \frac{4}{45}$ 6) $4 \frac{7}{18}$