口算:⑴4×5=□,8-20=□,9×7=□,70-26=□;⑵27+33=□,3×6=□,60+28=□,100-45=□
8-5= 8+2= 9-7= 4+4= 10-5= 4+2=
7-4= 9-5= 5+5= 3+3= 7-7= 8-7=
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=