$\dfrac{\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{6}}:\dfrac{\dfrac{2}{5}\left(\dfrac{1}{4}+\dfrac{3}{7}+\dfrac{5}{9}\right)}{\dfrac{3}{20}+\dfrac{9}{35}+\dfrac{1}{3}}= \ ?$

Các câu hỏi liên quan