4+1= 5-2= 3+4= 2+2=
5-5= 8+0= 7-4= 9-3=
8-7= 7+2= 9-6= 4-1=
2+3= 4+3= 5+2= 6-5=
3+5= 2+6= 0+7= 9+1=
9-4= 10-7= 16-0= 15-5=
7+8= 6+5= 3+17= 11+9=
11-6= 12-9= 14-8= 16-7=
( )○( )=( )
345﹣298= 0.64÷0.8= ﹣ = × =
1÷0.05= 0.25×40= 2÷ = ×25%=
+0.625= ×= 24÷40%= 7.2÷0.9÷0.8=