估算.511×18≈902÷32≈361÷39≈
公交车上有16个人,到站后下了7个人,公交车上还有几个人?
冰箱里有15罐饮料,喝掉了7罐,冰箱里还剩下几罐饮料?
8-2= 8-5= 18-6= 12-1= 7-5= 12-2=
17-5= 17-3= 17-2= 17-1= 17-6= 17-4=
16-1= 16-3= 16-5=16-4= 16-0= 16-2=