Вычислите: 1 13/14 - (2 - 1 11/35) : 9/25 + 4/21

2. Вычислите: $1\frac{13}{14}-\left(2-1\frac{11}{35}\right):\frac{9}{25}+\frac{4}{21}$ 1) $2-1\frac{11}{35}=1\frac{35}{35}-1\frac{11}{35}=\frac{24}{35}$ 2) $\frac{24}{35}:\frac{9}{25}=\frac{24}{35}\cdot\frac{25}{9}=\frac{8\cdot5}{7\cdot3}=\frac{40}{21}=1\frac{19}{21}$ 3) $1\frac{13}{14}-1\frac{19}{21}=\frac{27}{14}-\frac{40}{21}=\frac{81-80}{42}=\frac{1}{42}$ 4) $\frac{1}{42}+\frac{4}{21}=\frac{1+8}{42}=\frac{9}{42}=\frac{3}{14}$ **Ответ: $\frac{3}{14}$** 3. Вычислите: $3\frac{9}{10}-\left(2-1\frac{11}{35}\right):\frac{9}{49}+\frac{1}{2}$ 1) $2-1\frac{11}{35}=\frac{24}{35}$ 2) $\frac{24}{35}:\frac{9}{49}=\frac{24\cdot49}{35\cdot9}=\frac{8\cdot7}{5\cdot3}=\frac{56}{15}=3\frac{11}{15}$ 3) $3\frac{9}{10}-3\frac{11}{15}=\frac{39}{10}-\frac{56}{15}=\frac{117-112}{30}=\frac{5}{30}=\frac{1}{6}$ 4) $\frac{1}{6}+\frac{1}{2}=\frac{1+3}{6}=\frac{4}{6}=\frac{2}{3}$ **Ответ: $\frac{2}{3}$** 4. Вычислите: $\frac{9}{10}+\frac{4}{9}:\left(2-1\frac{11}{21}\right)-1\frac{2}{3}$ 1) $2-1\frac{11}{21}=1\frac{21}{21}-1\frac{11}{21}=\frac{10}{21}$ 2) $\frac{4}{9}:\frac{10}{21}=\frac{4\cdot21}{9\cdot10}=\frac{2\cdot7}{3\cdot5}=\frac{14}{15}$ 3) $\frac{9}{10}+\frac{14}{15}=\frac{27+28}{30}=\frac{55}{30}=\frac{11}{6}=1\frac{5}{6}$ 4) $1\frac{5}{6}-1\frac{2}{3}=\frac{5}{6}-\frac{4}{6}=\frac{1}{6}$ **Ответ: $\frac{1}{6}$**