Контрольная работа. ВАРИАНТ 1 13 1. Вычислите: 14-(2-1 11 35):25+21

1. Вычислите: $$1\frac{13}{14}-(2-1\frac{11}{35}):\frac{9}{25}+\frac{4}{21}$$

1) $$2-1\frac{11}{35}=1\frac{35}{35}-1\frac{11}{35}=\frac{35-11}{35}=\frac{24}{35}$$

2) $$1\frac{13}{14}=\frac{14+13}{14}=\frac{27}{14}$$

3) $$\frac{24}{35}:\frac{9}{25}=\frac{24}{35}\cdot\frac{25}{9}=\frac{24\cdot25}{35\cdot9}=\frac{8\cdot5}{7\cdot3}=\frac{40}{21}$$

4) $$\frac{27}{14}+\frac{4}{21}=\frac{27 \cdot 3}{14 \cdot 3}+\frac{4 \cdot 2}{21 \cdot 2}=\frac{81}{42}+\frac{8}{42}=\frac{81+8}{42}=\frac{89}{42}=2\frac{5}{42}$$

5) $$2\frac{5}{42}-\frac{40}{21}=2\frac{5}{42}-\frac{40 \cdot 2}{21 \cdot 2}=2\frac{5}{42}-\frac{80}{42}=1\frac{47}{42}-\frac{80}{42}=1\frac{47-80}{42}=1\frac{-33}{42}=1-\frac{33}{42}=\frac{42}{42}-\frac{33}{42}=\frac{9}{42}=\frac{3}{14}$$

Ответ: $$\frac{3}{14}$$