Вычисли: (1/2 − 1/3) / (5/6); (1/3 + 1/4) / 7; 4 / (1/9 − 1/18); (1/2 + 2/3) / (7/9).

1. \(\dfrac{\dfrac{1}{2}-\dfrac{1}{3}}{\dfrac{5}{6}}=\dfrac{\dfrac{1}{6}}{\dfrac{5}{6}}=\dfrac{1}{5}\).
2. \(\dfrac{\dfrac{1}{3}+\dfrac{1}{4}}{7}=\dfrac{\dfrac{7}{12}}{7}=\dfrac{1}{12}\).
3. \(\dfrac{4}{\dfrac{1}{9}-\dfrac{1}{18}}=\dfrac{4}{\dfrac{1}{18}}=72\).
4. \(\dfrac{\dfrac{1}{2}+\dfrac{2}{3}}{\dfrac{7}{9}}=\dfrac{\dfrac{7}{6}}{\dfrac{7}{9}}=\dfrac{3}{2}\).

Ответ: 1/5; 1/12; 72; 3/2.