2. Вычислите: 1)-27+14+(-80)+21+ (-28); 2) -3,27+ (-4,84) + 6,51+ (-2,64) + 7,65; 3) \frac{11}{48}+\frac{13}{72}+(-\frac{17}{48})+(-\frac{7}{72}).

Ответ: 1) -100; 2) 3,31; 3) -1/6

1) \[-27+14+(-80)+21+ (-28) = -27 + 14 - 80 + 21 - 28 = -13 - 80 + 21 - 28 = -93 + 21 - 28 = -72 - 28 = -100\]

2) \[-3,27+ (-4,84) + 6,51+ (-2,64) + 7,65 = -3,27 - 4,84 + 6,51 - 2,64 + 7,65 = -8,11 + 6,51 - 2,64 + 7,65 = -1,6 + (-2,64) + 7,65 = -4,24 + 7,65 = 3,41\]

3) \[\frac{11}{48}+\frac{13}{72}+(-\frac{17}{48})+(-\frac{7}{72}) = \frac{11}{48} + \frac{13}{72} - \frac{17}{48} - \frac{7}{72} = (\frac{11}{48} - \frac{17}{48}) + (\frac{13}{72} - \frac{7}{72}) = \frac{-6}{48} + \frac{6}{72} = \frac{-1}{8} + \frac{1}{12} = \frac{-3}{24} + \frac{2}{24} = \frac{-1}{24}\]

Ответ: 1) -100; 2) 3,41; 3) -1/24