Làm nhanh với nhé cảm ơn

$\left.\begin{array}{l}6420\\\quad\!\!\!180\ \\\!\!\!\quad180\\\\\end{array}\right|\!\!\!\;\!\!\begin{array}{l}\dfrac{\ \ 312\ \ }{\ \ 20\ \ }\\\\\\\end{array}$

Vậy `6420 : 312 = 20` (dư `180`)

`#HPHG`