Решение: Карточка №9. Найти значение выражения

Карточка №9. Найдите значение выражения: 1. \(\frac{1}{4} - \frac{21}{50} = \frac{25}{100} - \frac{42}{100} = -\frac{17}{100} = -0,17\) 2. \(\frac{1}{2} + \frac{11}{5} = 0,5 + 2,2 = 2,7\) 3. \(\frac{6}{5 \cdot 4} = \frac{6}{20} = \frac{3}{10} = 0,3\) 4. \(\frac{1}{1 + \frac{1}{3}} = \frac{1}{\frac{4}{3}} = \frac{3}{4} = 0,75\) 5. \(\frac{1}{\frac{1}{42} - \frac{1}{91}} = \frac{1}{\frac{13}{546} - \frac{6}{546}} = \frac{1}{\frac{7}{546}} = \frac{546}{7} = 78\) 6. \((\frac{7}{22} + \frac{14}{11}) : \frac{10}{33} = (\frac{7}{22} + \frac{28}{22}) \cdot \frac{33}{10} = \frac{35}{22} \cdot \frac{33}{10} = \frac{7}{2} \cdot \frac{3}{2} = \frac{21}{4} = 5,25\) 7. \((2\frac{3}{4} + 2\frac{1}{5}) \cdot 16 = (2,75 + 2,2) \cdot 16 = 4,95 \cdot 16 = 79,2\) 8. \(4\frac{3}{13} : (\frac{6}{17} - 2\frac{8}{13}) = \frac{55}{13} : (\frac{6 \cdot 13 - 34 \cdot 17}{17 \cdot 13}) = \frac{55}{13} : \frac{78 - 578}{221} = \frac{55}{13} \cdot (-\frac{221}{500}) = \frac{55}{13} \cdot (-\frac{17 \cdot 13}{500}) = -\frac{55 \cdot 17}{500} = -\frac{11 \cdot 17}{100} = -1,87\) 9. \(10 \cdot (\frac{1}{5})^2 - 12 \cdot \frac{1}{5} = 10 \cdot \frac{1}{25} - \frac{12}{5} = \frac{2}{5} - \frac{12}{5} = -\frac{10}{5} = -2\) 10. \((\frac{4}{15} + \frac{19}{25}) \cdot \frac{6}{7} = (\frac{20}{75} + \frac{57}{75}) \cdot \frac{6}{7} = \frac{77}{75} \cdot \frac{6}{7} = \frac{11}{25} \cdot 2 = \frac{22}{25} = 0,88\)