tính nhanh: 3/5:(1/2.3/5)

$\dfrac{3}{5}$`:`$\left(\dfrac{1}{2} . \dfrac{3}{5}\right)$

`=`$\dfrac{3}{5}$`:`$\dfrac{3}{5}$`:`$\dfrac{1}{2}$

`=1:`$\dfrac{1}{2}$

`=2`