theo de bai so lon chia so be duoc 13 va 12 don vi vay so lon gap 13 lan va 12 don vi so be ta co so do:
so be 1 phan, so lon 13 phan va 12 don vi tong la 250
vay tong so phan la:13 phan 12 don vi +1phan=14phan va 12don vi
so be la :[250 - 12]:14=17[don vi]
so lon la:17x13+12=233[don vi]