直接写出得数。①39÷3= ②80÷20= ③640÷80= ④800÷400= ⑤240÷60=⑥20×5= ⑦270÷90= ⑧570÷3= ⑨3500÷700= ⑩900÷100=
5+3= 5-3= 6-6= 8+1= 9+1= 10-4=
6-5= 10-5= 4+3= 2+2= 2+1= 6-5=
8+2= 7-5= 7+2= 10-10= 9-9= 1+1=
10-3= 6+1= 9+1= 8-3= 9-6= 4+3=
5-5= 6+0= 7-7= 4+0= 9+0= 10-9=