公分母复习

${\displaystyle \frac{7}{8}}\times {\displaystyle \frac{}{5}}={\displaystyle \frac{}{40}}$‍

${\displaystyle \frac{3}{10}}\times {\displaystyle \frac{}{4}}={\displaystyle \frac{}{40}}$‍

${\displaystyle \frac{7}{8}}\times {\displaystyle \frac{5}{5}}={\displaystyle \frac{35}{40}}$‍

${\displaystyle \frac{3}{10}}\times {\displaystyle \frac{4}{4}}={\displaystyle \frac{12}{40}}$‍

${\displaystyle \frac{7}{8}}={\displaystyle \frac{35}{40}}$‍

${\displaystyle \frac{3}{10}}={\displaystyle \frac{12}{40}}$‍