计算直接写出得数。900÷30= 630÷90= 78÷13= 320÷40=860÷20= 70÷35= 51÷17= 400÷50=300÷l0= 92÷4= 450÷90= 420÷70=
5+0= 10-2= 5-2= 7-3= 6-4= 8-4=
10-6= 8-6= 8-5=8-3= 5-4= 5-1=
4+2= 7-4= 7-6 =10-8= 10-3= 5+3=
6+3= 7+2= 9+1=7+1= 8-5= 6-3=
8-4= 6+0= 5+2=10-9= 10-8= 8+2=