$\color{lightblue}{\text{o Lâm Vũ}}$

`a` ) $\dfrac{7}{2}$ - $\dfrac{1}{3}$

= $\dfrac{21}{6}$ - $\dfrac{2}{6}$

= $\dfrac{19}{6}$

`b` ) $\dfrac{3}{11}$ x $\dfrac{6}{8}$

= $\dfrac{3}{11}$ x $\dfrac{3}{4}$

= $\dfrac{9}{44}$

`c` ) $\dfrac{3}{5}$ : `2`

= $\dfrac{3}{5}$ x $\dfrac{1}{2}$

= $\dfrac{3}{10}$