Đáp án:
Giải thích các bước giải:
90=2.3.3.5 Ư={1,2,5,6,9,15,18,30,45,90}
124=2.2.31 Ư={1,2,4,62,31,124}
300=2.2.3.5.5 Ư={1,2,3,4,5,6,,10,12,15,20,25,30,50,60,75,100,150,300}
78=2.3.13 Ư={1,2,3,6,13,26,39,78}
96=2.2.2.2.2.3 Ư={1,2,3,4,8,12,24,32,48,96}
suy ra ta thấy ƯC={90,124,300,78,96}=2