1) (-2,6 · 5) : 5 =

1) $(-2,6 \cdot 5) : 5 = -13 : 5 = -2,6$ 2) $(-8 \cdot 6,9) : (-6,9) = -8 \cdot (6,9 : (-6,9)) = -8 \cdot (-1) = 8$ 3) $200 : ((-4 \frac{1}{4}) : 8 \frac{1}{2}) = 200 : (-\frac{17}{4} : \frac{17}{2}) = 200 : (-\frac{17}{4} \cdot \frac{2}{17}) = 200 : (-\frac{1}{2}) = -400$ 4) $(-2 \frac{2}{3}) : (1 \frac{1}{3} : (-2 \frac{2}{3})) = -\frac{8}{3} : (\frac{4}{3} : (-\frac{8}{3})) = -\frac{8}{3} : (\frac{4}{3} \cdot (-\frac{3}{8})) = -\frac{8}{3} : (-\frac{1}{2}) = -\frac{8}{3} \cdot (-2) = \frac{16}{3} = 5 \frac{1}{3}$ 5) $(19 \frac{1}{4} - 18 \frac{5}{6}) + (27 - 26 \frac{13}{24}) = (19 \frac{3}{12} - 18 \frac{10}{12}) + (26 \frac{24}{24} - 26 \frac{13}{24}) = (18 \frac{15}{12} - 18 \frac{10}{12}) + \frac{11}{24} = \frac{5}{12} + \frac{11}{24} = \frac{10}{24} + \frac{11}{24} = \frac{21}{24} = \frac{7}{8}$ 6) $(8 \frac{5}{9} - 10) + (14 \frac{1}{6} - 18 \frac{14}{27}) = (8 \frac{5}{9} - 9 \frac{9}{9}) + (14 \frac{9}{54} - 18 \frac{28}{54}) = -1 \frac{4}{9} + (14 \frac{9}{54} - 18 \frac{28}{54}) = -\frac{13}{9} + (\frac{765}{54} - \frac{998}{54}) = -\frac{78}{54} - \frac{233}{54} = -\frac{311}{54} = -5 \frac{41}{54}$ 7) $12 \frac{5}{8} - (11 \frac{5}{12} + 8 \frac{15}{16}) = 12 \frac{5}{8} - (11 \frac{20}{48} + 8 \frac{45}{48}) = 12 \frac{5}{8} - 19 \frac{65}{48} = 12 \frac{5}{8} - 20 \frac{17}{48} = 12 \frac{30}{48} - 20 \frac{17}{48} = -7 \frac{35}{48}$ 8) $(66 - 78) : 0,12 = -12 : 0,12 = -100$