Вариант 2. №1. Вычислите: 1) 2\(\frac{3}{5}\) \(\cdot\) \(\frac{25}{26}\) + 2\(\frac{1}{4}\) : \(\frac{27}{16}\) - 3\(\frac{5}{6}\); 2) -2,4 \(\cdot\) 3 + 0,21 : 0,07 + 15 \(\cdot\) (-0,3) + 9,7; 3) 8 + |4 - 52| - 2 \(\cdot\) |4,3 + 9,7|.

Решение:

1. \(2\frac{3}{5} \cdot \frac{25}{26} = \frac{13}{5} \cdot \frac{25}{26} = \frac{1}{1} \cdot \frac{5}{2} = \frac{5}{2} = 2.5\)
2. \(2\frac{1}{4} : \frac{27}{16} = \frac{9}{4} : \frac{27}{16} = \frac{9}{4} \cdot \frac{16}{27} = \frac{1}{1} \cdot \frac{4}{3} = \frac{4}{3}\)
3. \(3\frac{5}{6} = \frac{23}{6}\)
4. \(2.5 + \frac{4}{3} - \frac{23}{6} = \frac{5}{2} + \frac{4}{3} - \frac{23}{6} = \frac{15}{6} + \frac{8}{6} - \frac{23}{6} = \frac{15+8-23}{6} = \frac{0}{6} = 0\)
5. \(-2.4 \cdot 3 = -7.2\)
6. \(0.21 : 0.07 = 3\)
7. \(15 \cdot (-0.3) = -4.5\)
8. \(-7.2 + 3 - 4.5 + 9.7 = -4.2 - 4.5 + 9.7 = -8.7 + 9.7 = 1\)
9. \(|4 - 52| = |-48| = 48\)
10. \(|4.3 + 9.7| = |14| = 14\)
11. \(8 + 48 - 2 \cdot 14 = 56 - 28 = 28\)

Ответ: 1) 0; 2) 1; 3) 28.