Карточка №3 Найдите значение выражения: 1. 1/10 + 21/50

1. $\frac{1}{10} + \frac{21}{50} = \frac{5}{50} + \frac{21}{50} = \frac{26}{50} = \frac{13}{25} = 0,52$ 2. $\frac{3}{2} - \frac{9}{5} = \frac{15}{10} - \frac{18}{10} = -\frac{3}{10} = -0,3$ 3. $\frac{19}{5 \cdot 4} = \frac{19}{20} = 0,95$ 4. $\frac{1,3}{1 + \frac{1}{4}} = \frac{1,3}{1,25} = \frac{130}{125} = \frac{26}{25} = 1,04$ 5. $\frac{1}{\frac{1}{9} - \frac{1}{12}} = \frac{1}{\frac{4}{36} - \frac{3}{36}} = \frac{1}{\frac{1}{36}} = 36$ 6. $(\frac{7}{16} - \frac{1}{32}) : \frac{11}{24} = (\frac{14}{32} - \frac{1}{32}) : \frac{11}{24} = \frac{13}{32} \cdot \frac{24}{11} = \frac{13 \cdot 3}{4 \cdot 11} = \frac{39}{44}$ 7. $(\frac{4}{9} - 3 \frac{1}{15}) \cdot 9 = (\frac{4}{9} - \frac{46}{15}) \cdot 9 = \frac{4}{9} \cdot 9 - \frac{46}{15} \cdot 9 = 4 - \frac{46 \cdot 3}{5} = 4 - \frac{138}{5} = 4 - 27,6 = -23,6$ 8. $2 \frac{2}{5} : (\frac{9}{10} - 1 \frac{5}{14}) = 2,4 : (0,9 - \frac{19}{14}) = 2,4 : (\frac{9}{10} - \frac{19}{14}) = 2,4 : (\frac{63}{70} - \frac{95}{70}) = 2,4 : (-\frac{32}{70}) = \frac{12}{5} \cdot (-\frac{70}{32}) = \frac{3 \cdot (-14)}{4} = -\frac{42}{4} = -10,5$ 9. $6 \cdot (\frac{1}{3})^2 - 8 \cdot \frac{1}{3} = 6 \cdot \frac{1}{9} - \frac{8}{3} = \frac{6}{9} - \frac{8}{3} = \frac{2}{3} - \frac{8}{3} = -\frac{6}{3} = -2$ 10. $(\frac{5}{33} - \frac{8}{15}) \cdot \frac{11}{5} = (\frac{25}{165} - \frac{88}{165}) \cdot \frac{11}{5} = (-\frac{63}{165}) \cdot \frac{11}{5} = -\frac{63 \cdot 11}{165 \cdot 5} = -\frac{63}{15 \cdot 5} = -\frac{63}{75} = -\frac{21}{25} = -0,84$