3. Комбо! Вычислите: 1) (9,5 + 8,9) / 2,3; 2) (4,6 + 2,8) / 0,2; 3) (11,8 + 2,7) / 2,9; 4) (6,8 − 4,7) / 1,4; 5) (2,3 − 6,8) / 1,5; 6) (3,9 − 1,8) / 0,3; 7) 1,5 / (1 + 1/5); 8) 1,9 / (2/3 + 3/5); 9) 2,6 / (4/5 + 1/2); 10) 1 / (1/18 − 1/21); 11) 1 / (1/35 − 1/60); 12) 1 / (1/42 − 1/91).

1. \(\dfrac{9.5+8.9}{2.3}=\dfrac{18.4}{2.3}=8\).
2. \(\dfrac{4.6+2.8}{0.2}=\dfrac{7.4}{0.2}=37\).
3. \(\dfrac{11.8+2.7}{2.9}=\dfrac{14.5}{2.9}=5\).
4. \(\dfrac{6.8-4.7}{1.4}=\dfrac{2.1}{1.4}=1.5\).
5. \(\dfrac{2.3-6.8}{1.5}=\dfrac{-4.5}{1.5}=-3\).
6. \(\dfrac{3.9-1.8}{0.3}=\dfrac{2.1}{0.3}=7\).
7. \(\dfrac{1.5}{1+\frac{1}{5}}=\dfrac{1.5}{1.2}=1.25\).
8. \(\dfrac{1.9}{\frac{2}{3}+\frac{3}{5}}=\dfrac{1.9}{\frac{10}{15}+\frac{9}{15}}=\dfrac{1.9}{\frac{19}{15}}=1.5\).
9. \(\dfrac{2.6}{\frac{4}{5}+\frac{1}{2}}=\dfrac{2.6}{\frac{8}{10}+\frac{5}{10}}=\dfrac{2.6}{1.3}=2\).
10. \(\dfrac{1}{\frac{1}{18}-\frac{1}{21}}=\dfrac{1}{\frac{21-18}{378}}=\dfrac{1}{\frac{1}{126}}=126\).
11. \(\dfrac{1}{\frac{1}{35}-\frac{1}{60}}=\dfrac{1}{\frac{60-35}{2100}}=\dfrac{1}{\frac{1}{84}}=84\).
12. \(\dfrac{1}{\frac{1}{42}-\frac{1}{91}}=\dfrac{1}{\frac{91-42}{3822}}=\dfrac{1}{\frac{1}{78}}=78\).

Ответ: 1) 8; 2) 37; 3) 5; 4) 1,5; 5) −3; 6) 7; 7) 1,25; 8) 1,5; 9) 2; 10) 126; 11) 84; 12) 78.