\(\dfrac{20}{50}x\dfrac{150}{120}\)

ừ

\(2\dfrac{1}{3}x5\dfrac{1}{4}=\dfrac{7}{3}x\dfrac{21}{4}=\dfrac{49}{4}\)

\(3\dfrac{2}{5}x2\dfrac{1}{7}=\dfrac{17}{5}x\dfrac{15}{7}=\dfrac{17x5x3}{5x7}=\dfrac{51}{7}\)

\(8\dfrac{1}{6}:2\dfrac{1}{2}=\dfrac{49}{6}:\dfrac{5}{2}=\dfrac{49}{6}x\dfrac{2}{5}=\dfrac{49x2}{3x2x5}=\dfrac{49}{15}\)