\(\dfrac{3}{5}+\dfrac{2}{3}=\dfrac{9}{15}+\dfrac{10}{15}=\dfrac{19}{15}\\ \dfrac{5}{7}-\dfrac{1}{2}=\dfrac{10}{14}-\dfrac{7}{14}=\dfrac{3}{14}\\ \dfrac{5}{6}\times\dfrac{4}{5}=\dfrac{1}{3}\times\dfrac{2}{1}=\dfrac{2}{3}\\ \dfrac{7}{9}:\dfrac{4}{3}=\dfrac{7}{9}\times\dfrac{3}{4}=\dfrac{7}{12}\)
\(\dfrac{3}{5}+\dfrac{2}{3}=\dfrac{9}{15}+\dfrac{10}{15}=\dfrac{19}{15}\)
\(\dfrac{5}{7}-\dfrac{1}{2}=\dfrac{10}{14}-\dfrac{7}{14}=\dfrac{3}{14}\)
\(\dfrac{5}{6}\text{×}\dfrac{4}{5}=\dfrac{5\text{×}4}{6\text{×}5}=\dfrac{2}{3}\)
\(\dfrac{7}{9}:\dfrac{4}{3}=\dfrac{7}{9}\text{×}\dfrac{3}{4}=\dfrac{7\text{×}3}{9\text{×}4}=\dfrac{7\text{×}3}{3\text{×}3\text{×}4}=\dfrac{7}{12}\)
\(\dfrac{3}{5}+\dfrac{2}{3}=\dfrac{9}{15}+\dfrac{10}{15} = \dfrac{19}{15}\)
\(\dfrac{5}{7}-\dfrac{1}{2}=\dfrac{10}{14}-\dfrac{7}{14}=\dfrac{3}{14}\)
\(\dfrac{5}{6} \times \dfrac{4}{5} = \dfrac{4}{6}= \dfrac{2}{3}\)
\( \dfrac{7}{9} : \dfrac{4}{3} = \dfrac{7}{9} \times \dfrac{3}{4} = \dfrac{7}{12}\)