Вариант 2 1. Найдите значение выражения: 11 1 a) 7:3

Решение:

$$7\frac{11}{12} : 3\frac{1}{6} = \frac{7 \cdot 12 + 11}{12} : \frac{3 \cdot 6 + 1}{6} = \frac{84 + 11}{12} : \frac{18 + 1}{6} = \frac{95}{12} : \frac{19}{6} = \frac{95}{12} \cdot \frac{6}{19} = \frac{95 \cdot 6}{12 \cdot 19} = \frac{5 \cdot 1}{2 \cdot 1} = \frac{5}{2} = 2\frac{1}{2} = 2,5$$.

$$ \frac{2}{3\frac{5}{5}} = \frac{2}{3 + 1} = \frac{2}{4} = \frac{1}{2} = 0,5$$.

б) $$ \frac{2}{3\frac{5}{5}} = \frac{2}{3 + 1} = \frac{2}{4} = \frac{1}{2} = 0,5$$.

в) $$ \frac{3,4}{20,4}=\frac{34}{204}=\frac{17}{102}=\frac{1}{6}$$.

г) $$ \frac{1,71}{4\frac{1}{5}}=\frac{1,71}{\frac{4 \cdot 5 + 1}{5}}=\frac{1,71}{\frac{21}{5}}=1,71:\frac{21}{5}=\frac{171}{100}:\frac{21}{5}=\frac{171}{100} \cdot \frac{5}{21}=\frac{171 \cdot 5}{100 \cdot 21}=\frac{57 \cdot 1}{20 \cdot 7}=\frac{57}{140}$$.

Ответ: a) $$2,5$$, б) $$0,5$$, в) $$\frac{1}{6}$$, г) $$\frac{57}{140}$$.