Вычисли значения выражений с 1-го по 20-е задание

1) $\frac{5}{6} - \frac{3}{4} = \frac{10}{12} - \frac{9}{12} = \frac{1}{12}$ 2) $\frac{9}{14} + \frac{8}{21} = \frac{27}{42} + \frac{16}{42} = \frac{43}{42} = 1\frac{1}{42}$ 3) $\frac{7}{9} + \frac{5}{12} - \frac{3}{4} = \frac{28}{36} + \frac{15}{36} - \frac{27}{36} = \frac{16}{36} = \frac{4}{9}$ 4) $3\frac{5}{8} + 1\frac{2}{3} = \frac{29}{8} + \frac{5}{3} = \frac{87}{24} + \frac{40}{24} = \frac{127}{24} = 5\frac{7}{24}$ 5) $4\frac{4}{9} - 2\frac{5}{6} = \frac{40}{9} - \frac{17}{6} = \frac{80}{18} - \frac{51}{18} = \frac{29}{18} = 1\frac{11}{18}$ 6) $6\frac{7}{12} + (5\frac{3}{40} - 4\frac{8}{15}) = 6\frac{7}{12} + (\frac{203}{40} - \frac{68}{15}) = 6\frac{7}{12} + (\frac{609}{120} - \frac{544}{120}) = 6\frac{7}{12} + \frac{65}{120} = 6\frac{7}{12} + \frac{13}{24} = 6\frac{14}{24} + \frac{13}{24} = 6\frac{27}{24} = 7\frac{3}{24} = 7\frac{1}{8}$ 7) $3\frac{3}{4} \cdot 1\frac{7}{9} = \frac{15}{4} \cdot \frac{16}{9} = \frac{15 \cdot 4}{1 \cdot 9} = \frac{60}{9} = \frac{20}{3} = 6\frac{2}{3}$ 8) $\frac{3}{4} \cdot \frac{2}{9} = \frac{1}{2} \cdot \frac{1}{3} = \frac{1}{6}$ 9) $4\frac{1}{2} : 5\frac{1}{4} = \frac{9}{2} : \frac{21}{4} = \frac{9}{2} \cdot \frac{4}{21} = \frac{9 \cdot 2}{1 \cdot 21} = \frac{18}{21} = \frac{6}{7}$ 10) $-2,7 - 1,5 = -4,2$ 11) $5,4 - 7,1 = -1,7$ 12) $-3,7 + 5,6 = 1,9$ 13) $-\frac{7}{9} + \frac{5}{6} = -\frac{14}{18} + \frac{15}{18} = \frac{1}{18}$ 14) $-2\frac{1}{8} - 1\frac{5}{16} = -\frac{17}{8} - \frac{21}{16} = -\frac{34}{16} - \frac{21}{16} = -\frac{55}{16} = -3\frac{7}{16}$ 15) $-4,3 \cdot (-5,7) = 24,51$ 16) $-1\frac{1}{7} \cdot 1\frac{5}{16} = -\frac{8}{7} \cdot \frac{21}{16} = -\frac{1 \cdot 3}{1 \cdot 2} = -\frac{3}{2} = -1,5$ 17) $-25,344 : (-3,6) = 7,04$ 18) $1\frac{1}{8} : (-3\frac{3}{8}) = \frac{9}{8} : (-\frac{27}{8}) = \frac{9}{8} \cdot (-\frac{8}{27}) = \frac{1}{1} \cdot (-\frac{1}{3}) = -\frac{1}{3}$ 19) $\frac{9,62 - 5\frac{5}{6} \cdot \frac{3}{5}}{1,9 + 1,7} = \frac{9,62 - \frac{35}{6} \cdot \frac{3}{5}}{3,6} = \frac{9,62 - \frac{7}{2}}{3,6} = \frac{9,62 - 3,5}{3,6} = \frac{6,12}{3,6} = 1,7$ 20) $(-48\frac{3}{4} : 3,9 + 8\frac{1}{5}) \cdot (-6,3) = (-\frac{195}{4} : 3,9 + \frac{41}{5}) \cdot (-6,3) = (-\frac{195}{4} : \frac{39}{10} + \frac{41}{5}) \cdot (-6,3) = (-\frac{195}{4} \cdot \frac{10}{39} + \frac{41}{5}) \cdot (-6,3) = (-\frac{5 \cdot 5}{2 \cdot 1} + \frac{41}{5}) \cdot (-6,3) = (-\frac{25}{2} + \frac{41}{5}) \cdot (-6,3) = (-\frac{125}{10} + \frac{82}{10}) \cdot (-6,3) = -\frac{43}{10} \cdot (-6,3) = -4,3 \cdot (-6,3) = 27,09$