1. Вычислите: 1 - 3/7 : 9/14 (ответ запишите в виде дроби)

1. $1 - \frac{3}{7} : \frac{9}{14} = 1 - (\frac{3}{7} \cdot \frac{14}{9}) = 1 - (\frac{1}{1} \cdot \frac{2}{3}) = 1 - \frac{2}{3} = \frac{1}{3}$ 2. $-1,75 - (-8,7 + 6,3) = -1,75 - (-2,4) = -1,75 + 2,4 = 0,65$ 3. $1 \frac{2}{5} + \frac{3}{8} - \frac{39}{40} = \frac{7}{5} + \frac{3}{8} - \frac{39}{40} = \frac{56}{40} + \frac{15}{40} - \frac{39}{40} = \frac{32}{40} = \frac{4}{5} = 0,8$ 4. $\frac{-9 - 0,1}{2,8} = \frac{-9,1}{2,8} = -\frac{91}{28} = -3,25$ 5. $\frac{7}{2} : (\frac{7}{8} - \frac{3}{4}) = \frac{7}{2} : (\frac{7}{8} - \frac{6}{8}) = \frac{7}{2} : \frac{1}{8} = \frac{7}{2} \cdot 8 = 28$ 6. $\frac{55}{8} : \frac{11}{48} \cdot \frac{5}{6} = (\frac{55}{8} \cdot \frac{48}{11}) \cdot \frac{5}{6} = (5 \cdot 6) \cdot \frac{5}{6} = 30 \cdot \frac{5}{6} = 25$ 7. $\frac{5}{2} : (\frac{5}{6} - \frac{2}{3}) = \frac{5}{2} : (\frac{5}{6} - \frac{4}{6}) = \frac{5}{2} : \frac{1}{6} = \frac{5}{2} \cdot 6 = 15$ 8. $\frac{4,9}{5,6 - 8,4} = \frac{4,9}{-2,8} = -\frac{49}{28} = -\frac{7}{4} = -1,75$ 9. $1 - \frac{3}{8} \cdot 3 \frac{1}{5} = 1 - (\frac{3}{8} \cdot \frac{16}{5}) = 1 - (\frac{3}{1} \cdot \frac{2}{5}) = 1 - \frac{6}{5} = -\frac{1}{5} = -0,2$ 10. $\frac{25}{4} : \frac{6}{5} : \frac{15}{8} = \frac{25}{4} \cdot \frac{5}{6} \cdot \frac{8}{15} = \frac{25 \cdot 5 \cdot 8}{4 \cdot 6 \cdot 15} = \frac{1000}{360} = \frac{100}{36} = \frac{25}{9} = 2 \frac{7}{9}$ 11. $\frac{2}{9} + \frac{4}{7} : \frac{9}{28} = \frac{2}{9} + (\frac{4}{7} \cdot \frac{28}{9}) = \frac{2}{9} + \frac{16}{9} = \frac{18}{9} = 2$ 12. $3 \frac{11}{15} : \frac{4}{5} + \frac{1}{3} = \frac{56}{15} \cdot \frac{5}{4} + \frac{1}{3} = \frac{14}{3} + \frac{1}{3} = \frac{15}{3} = 5$ 13. $1 - \frac{3}{7} \cdot 2 \frac{5}{8} = 1 - (\frac{3}{7} \cdot \frac{21}{8}) = 1 - (\frac{3}{1} \cdot \frac{3}{8}) = 1 - \frac{9}{8} = -\frac{1}{8} = -0,125$ 14. $\frac{8}{9} - \frac{5}{12} \cdot \frac{8}{15} = \frac{8}{9} - (\frac{1}{3} \cdot \frac{2}{3}) = \frac{8}{9} - \frac{2}{9} = \frac{6}{9} = \frac{2}{3}$ 15. $1 \frac{2}{11} + \frac{2}{5} - \frac{37}{55} = \frac{13}{11} + \frac{2}{5} - \frac{37}{55} = \frac{65}{55} + \frac{22}{55} - \frac{37}{55} = \frac{50}{55} = \frac{10}{11}$ 16. $\frac{6,7 - 2,5}{2,4} = \frac{4,2}{2,4} = \frac{42}{24} = \frac{7}{4} = 1,75$